Thanks for the mention sir ! really appreciated! That may be off topic but the counter we have for Alpha and Beta made by Tennelec, use a methane/Argon mixture. This is an interesting experiment! I will try it and get back to you! I have an old UVC lamp I can dig up.. I must admit, you are doing everyone interested in the subject a very valuable service ! We should all be grateful for your content, Thank you for doing these reviews and experiments! This channel will go far for sure!
right now, in alternative reality, something bad might be happening to an alternative version of you, we must be careful what we say to Uncle Ri... I mean Neptunium!
I was somewhat alarmed when my (un-cased) Geiger counter started going crazy when I took it outside on a sunny day. I eventually calmed down and put it down to either high humidity or the photoelectric effect and not a crazy radiation event.
I got a newer version of GC-01. It came with an unmarked tube that looked like the 613 junk. It was not as sensitive to the americium source as it should have been, but would go to alarm condition if the tube was exposed to sunlight through a window. I live in Florida and the UV index was high in summer when I did this. A lot of the UV gets through the glass windows then. I replaced the GM tube with a J321 and it worked similar as it should to the americium source. It did not react at all when directly exposed to sunlight through a window like the previous GM tube. I measured the voltage using a divider circuit similar to your experiment, and measured 525 volts. I was surprised at the voltage because the load resistor was 8.3 Meg Ohms. I did not change the load resistor because the unit works great as far as sensitivity to radiation goes. The newer unit came with a 300 MAH battery which was a ripoff (I replaced it with a 1,100 MAH battery). It also has no backup battery, a USB that only charges the battery, and a smaller speaker/buzzer. The only positive aspect is: It is very easy to make the unit click on radiation counts. There are two resistors on the circuit board right next to each other (R16 and R36). R36 is the load resistor for the speaker/buzzer, and R16 is the load resistor for the LED on the other side of the circuit board. If you solder a tiny piece of wire between the upstream side of R16 and R36, the unit will click with a neat sound. Also when in alarm mode you can hear the clicks and the alarm tone. No resistors or capacitors required.
Great feedback, sadly this manufacturer is on the race to the bottom, they have just released the GC-02 which has all of the most terrible permutations that they have tried on the GC-01, combined into one product.
Adi makes a ,140v opamp, arranged for higher voltage. If you tickle the dragons tail, pre ionization you can take an ac coupled reading. Perfectly flat and you can distinguish the particle energy and light. It will measure vibration too. A neon bulb will work also. Not to mention adapting to different tubes.
@@project-326 Running it on a current source. You won't need damping gases. I think this may be the way the tube is driven now. It wouldn't surprise me. The variation in applied voltage used to maintain constant current represents energy added externally. A drop in voltage indicates applied energy.
But the voltage would try to rise to absolutely tremendous levels if you drive one from a pure current source. Between ionization events, the current is very close to zero. The tube is not a simple resistive load. With GM tubes, it is better to think in terms of charge instead of steady state currents. For accuracy, the tube voltage needs to be maintained within the Geiger plateau and that is why constant voltage supplies are used. The anode resistor does add some passive external quenching, but to stop the avalanche traveling the full length of the tube and further increasing the dead-time is what the quenching gas does. There are also active quenching systems (very high end) that actively pull the anode voltage down in a very short time after each activity, but I don't know of any commercial tubes that omit the quenching gasses altogether...
@@project-326it must be the same as a neon bulb. when you drive a neon bulb with a constant current it makes a radiation detector. Also you can measure vibration into hundreds of kilo hertz. Plus visible light. Anything to trigger excitaton will be compensated by the constant current source which manifests as a drop in voltage, which is your signal.
I´ve created this user and youtube channel just to share my results, as links are problematic. Thank you for your amazing research and videos. My video with results is already there. I´ve posted other comment on the community Studio 326 section .
This is fantastic! Wow, the voltage is super high, way beyond the plateau. The Helium/Neon tube discharges give a nice color, don't you think? What YT profile would you like me to credit with this?
@@project-326 Thanks! Now I know how difficult is to make a tiny simple video. Could be this one, who knows in future I post more videos will be on this account!
@@project-326 I mean, your project came just in time. Month back I was wondering that I should measure my CDV-700 output voltage. But now I also have a counter with J305ß tube connected to my smart home. So I've got the test subject freshly on hand.
@@project-326 Hmmm seems like this divider wasn't enough. Was able to make it and had a multiplier of 99.07. But for some reason my cheapo aliexpress geiger started counting like crazy, was able to measure voltage of 22,3V. Somethings wrong somewhere I guess
@@OH8EFI It can do that, usually the counting circuit is on the cathode. FOr the voltage measurement, it doesn't really matter if the tube starts counting.
Hi there. I understand the 100Mohm series resistor is to reduce the current when measuring the tube voltage, but am puzzled what the 1Mohm resister is for. (I’m a newbie in electronics). I wanted to also say thank you for this info, it’s very helpful, as I have recently purchased an old military dose rate trainer that uses a GM tube and am currently trying to fix it, and have been struggling to measure the tube voltage. Also just wanted to say what a fantastic entertaining and informative channel this is, and thank you for taking the time to make these videos. They are all excellent.
First of all, a hobby channel, I really appreciate your nice words. For the high impedance probe, the 100M resistor is to limit the current, as you already figured out, the 1M is for the multi-meter (DMM) to made a measurement against. Because the DMM typically has an input impedance of between 10M and 20M, the lower impedance will reduce the amount that the internal impedance will further reduce the measurement value by. In theory, you can just add a high impedance in series to make this measurement, and that is also valid, so long as you calibrate the measurement system before us on a low impedance voltage source. The purpose of the 1M resistor is to try and get a measurement ratio that is around 100:1, it just simplifies the process when there are two known values. That said, there is nothing wrong with just adding 100M in series with one of the leads of the meter...
Hi there. I measured the tube voltage on my Bosean FS-5000 using a 100M resistor in series with my Hantek DS02D15 oscilloscope, and it came in at 413volts rms. (Conveniently 120volts dc-rms=1.20volts dc-rms measured, so I figured 413volts=4.13volts measured) I hope my measurements were correct. I tried my cheapo UV flashlight and it had no effect. I will try to make a video at some point if I get the chance. I also measured the tube voltage of my old military Geiger and only got 205volts which explains why it’s not working. Love your videos. Please keep them coming
What an excellent bit of crowd science. I have a dental "UV" curing wand that operates at 428-480 nm with 1200 - 1500 mW/cm² output. Although they are often called UV the wavelength is too long and more in the visible violet region but it's high power and possibly spreads into the UV. I found however this had zero effect on the J321 tube in my GC-01 unit even when held closely at the cathode end. I have another UV torch of unspecified output for curing mobile phone display glass adhesive and that had no effect either. Neither did a small UV keyring banknote checker. I went outside in the sunlight and perhaps that did have an effect but it wasn't that marked. My J321 is being operated at 556V. I'm measuring with a x100 scope probe at the output of the voltage multiplier on the final capacitor C28 before the 2MΩ series limiting resistor R12 but despite this the voltage falls when the probe is first connected, to 516V due to the 100MΩ load and the effective impedance of the multiplier. From what you say the working voltage is set too high. I am thinking of adding two series connected 200V zener diodes at this point to ground to lower and stabilise the applied voltage to 400V rather than rely on the dubious loading resistor R38 which is set too high anyway.
The GC-01 has almost zero voltage regulation so they added a loading resistor (or at least a pad for it). In the end, I went for a 20M loading resistor. Ideally the J321 should be working at 380V but most manufacturers try to push this to the top end to give a higher sensitivity, which is fine, if the voltage is well regulated... Many viewers have found their own values between 5M and 20M to get the tube voltage correct. Just be sure to measure just the tube voltage without the anode resistor. Thanks for the nice feedback! :-)
@@project-326 I measured before the 2MΩ anode resistor on the capacitor C28 because the 100MΩ scope probe, when dabbed on instantly shows the full 556V stored on C28 which then exponentially discharges under the 100MΩ probe load to 516V. This can easily be captured on the scope and measured with the cursor. The initial 556V is also what I presume reaches the tube through the 2MΩ anode resistor when zero tube current flows (between clicks - confirmed by measuring across R12). If I were to measure directly at the tube after the 2MΩ anode resistor then because there is no capacitor to hold up the voltage, dabbing on the 100MΩ probe instantly divides with the 2MΩ resistor giving a false low voltage 100/102 x 556V = 545V which would then decay as C28 discharges but to an apparent lower 100/102 x 516V = 505V. Ok not a huge error of 11V and my scope probe will have a bigger error. However, I've just now added two 200V Zener diodes effectively across C28 which has greatly stabilised the voltage. It doesn't now dip down when the 100MΩ scope probe is applied. It measures at 428V which seems higher than expected. I did try to calibrate my 100MΩ scope probe against a 100V lab supply which when checked against my multimeter seems to read +2% high and as the 200V Zeners can be +/-6% so could read up to 432V - so it's within credibility. I also checked the supply current and it's unchanged which could have been an issue with pulling the multiplier down more but it seems fine. The units background reading seems to be unchanged.
did you notice any UV sensitivity before or after adding the Zener diodes? At background there will be very little difference, going from the middle of the plateau to the top of the range would result in about 5% increase in sensitivity, you would need to be able to average over a very long duration to be able to notice that... The tube voltage seems to be very high for the J321, are you getting any visible ionization (you need to look in a dark environment to see)?
Well it was high at a measured 556V which is why I added the Zeners and now it's about 420V given my attempts to calibrate the x100 probe. I've never seen any visible ionisation even with the UV sources but they might all be on the longer side of UV.
Your video was very well received and made a huge difference to my thinking about this project. Thank you for agreeing to me sharing this, your contribution was very helpful. Thanks!
Huh, just watching this video now. I just so happen to have a high voltage meter and real (higher frequency) UV pen light, along with the GC-01 that arrived today. It would be easy enough for me to test this, but making a video of it wold require a bit more work, since it's not something I typically do.
That's awesome. Don't forget the impedance issue - I used 100M/1M resistors in my probe to prevent the DMM impedance pulling the voltage down... I'll probably nag you later about the video, just record something quick and leave it to me to do the editing etc... ;-)
@@project-326 Thanks. If I remember correctly, it has a high resistance option too. I'll check tomorrow and maybe get around to making a quick video too. Cheers.
@@project-326 It's going to take a little longer than I thought. The "secret" high resistance mode (holding down the Hz % button while powering on) on my 87-V doesn't seem to be enough. The voltage was still being pulled down to 2 hundred something. I was able to test that there was a bit of UV sensitivity if I held the light near the negative side contact on the side of the tube, but not much of a change other than that. This is with the updated third-party firmware though, so if you want the stock firmware (mine shipped with v1.6), I can flash that back onto the GC-01. Cheers
You were staring down the barrel of the ones that showed the most harder UV production. Do not look at UV sources, put something that fluoresces or trust your detector.
Found it. Link below but probably gets deleted by UA-cam... [edit] Yup, they've deleted it. Imagine we could post a link in a comment, the horror! [/edit]
@@Muonium1 Strange, I just tested and it works for me. Mind you TaoBao is only available in China so you might be getting redirected if accessing from outside.
@@gblargg I just opened it up, its basically a piece of DVD glued over an OV2710 camera module with a 3D printed chassis to hold everything in exactly the right place. The design is actually quite nice, clearly the guy spent a lot of time getting the design to be just right. It does say "DIY" on the TaoBao ad... It works way better than the one I made a couple of years ago... I'm really not sure where you can get this in the US, there must be other folk doing something similar there?
@@project-326 That's actually inspiring, I didn't realize it was so easy. It sounds like that Theramino software for spectrometers is similar to sigrok for logic analyzers. I have one of those simple spectrometers you look through, with a diffraction grating. That would probably be easy to modify with a webcam.
@@gblargg I think that the time consuming bit is getting all of the alignments correct. For me, $49 is worth the time saved as I already have some other applications lined up for this device. I was actually surprised that I could perform some simple gas chromatography using this unit. It seems that the OV4710 camera module has a pretty wide spectral range, I think that the maker also removed the IR filter from the camera.
I am going to start on this project this week. I am a little bit late to the show but I will give my results. I have Crocodile clips (UK) Alligator clips(US) Gojira clips(JP) nipple clips (DE) GMC-300E+V4
@@project-326 My results from a GMC-300E-4V shrink tubed J-305 GM tube Powered the GMC300Ewith programmable DC pwr supply from 3.7v @800 ma to 9.1vdc @ 950ma. used 360 to 400nm UV light no excitation of tube, voltage at GM tube 410-411 VDC dropped to 408Vdc when excited by Thorium-232 source. My conclusion its, the Gas in the tube , its concentration and purity vary from tube to tube. I saved it all on video. How do I send you the video ?
I have a purple lazer pen. It illuminates LED lights. The lights all turn on . Some LEDS do nothing, others glow like the sun. If you twist the + and --- of the LED together , nothing happens. It doesn't light up afterwards.
Thanks for the idea - I took my violet laser and impressed the kids with a magic show, how I could make a white LED light-up in their hands without power! ;-)
After connecting my geiger to thingspeak and looking at graphs i noticed when my ws2812 led strips were on my j305 was reading very high. I ended up putting it back in its box for light sheilding. Is it only UV that effects tube? If so it confirms the ws2812 led puts off UV, This is something I have been wondering if they did since noticing the phosphor on a large cob led i have seems to glow yellow when under ws2812 lighting. Maybe ill make some vid's about it. Good channel keep up the good work.
What I am trying to test is the UV sensitivity mainly due to the tubes that are operating at the top of above the Geiger plateau range. It is common for manufacturers to have the tube voltage set high as it gives the impression of higher sensitivity. So far the results I have received seem to confirm that this is the case... Looking at the physics of a typical J321 tube, if the tube is being operated in the middle of the Geiger region, then in order to cause an ionization event from the photoelectric effect would require photons that are in the extreme UV range (
@@project-326 ahh sorry yeah manufacturer GQ electronics has started putting black sleeves over tubes to prevent any sensitivity. Sunlight is also a factor. I've brought one of these tubes in the sunlight with i assume overvoltad meter. and had it go crazy Also, do you have any source of directly talking to you as WeChat or Telegram
@@project-326 i don't have 100MΩ resistors, but i did an adjusted version of your experiment using a resistor divider with a 10MΩ and a 100kΩ. its dose rate alarm went off when probed (in the graph this reached 10kcpm), but i measured 3.03V which translates to 316.1V on the tube itself. device: FNIRST GC-01 (flashed with RadPro firmware) tube: J613 measured resistor values: Resistor 1: 10.29MΩ Resistor 2: 99.59kΩ uv led test (using 6 uv leds): there were no extra clicks detected, even while the uv leds were directly focused on the areas shown in video.
@@ThatJay283 Thank you for taking part in this experiment! Perhaps you can put 10 x 10M res in series? The main issue is that a 10M resistor will load the tiny HV power supply and pull the voltage down, hence the voltage you will read will be lower than the tube will normally be working at. Thanks!
I popped open a GMC-320+ V4... The tube has a heavy black plastic optical shroud, Shining my 365nm torch into the small exposed glass sections at each end didn't materially change the click rate... might look at probing the voltage later.
quite a few manufacturers are also still under the impression that UV sensitivity is from the tube and often use a piece of heat-shrink tube to cover it. I just cut mine off.
Presumably the typical 10 meg ohm of input impedance on a multimeter is way too low to have in parallel with the tube being similar in size to the anode resistor of the counter.
Because of the internal resistance of the measuring device, which loads the high -resistance voltage on the meter tube too much and therefore causes it to break down. A normal multimeter that measures up to 1000 volts has 10 MOhm internal resistance. With an anode resistance of 5 MOhm in front of the counting tube, the voltage collapses on 2/3. Sometimes the high voltage generator does not even manage to provide the flowing current of >20 µA. To use an Highly-Impedanced voltage divider is completely correct.
As other viewers have pointed out, its not a voltage rating issue. Some of the power supplies used on these devices can only source a few microamps of current, the GC-01 is a classic example. Normally a DMM has an input impedance in the region of 10 MOhms, so making the measurement actually changes the voltage level by a significant amount. Anyway, thank you for the comment, this channel is dedicated to learning so there are no dumb questions, please keep asking questions!
@@project-326 then what is it made of?! Because a lot of materials directly absorb UV radiation! There are only a few things that are transparent for short wave UV-C radiation!! Like quartz glass!! 🤷🏼♂️
@@TheOpticalFreakThe spectrometer doesn't claim it can measure UV-C. UV-C is 200-280nm, UV-B is 280-315nm and UV-A is 315-400nm. The spectrometer can only measure from 300nm upwards.
I usually record at 4K (I just use a cell phone camera, nothing special) so that when it gets transcoded back down to 1080p, less image quality is lost. I also helps in post processing, cropping the image won't have too much effect on the final result...
your are so right about that. YT seems to have their own video compression algo for storage and it works well on some parts of each video and is pretty terrible on other parts.
Let's do another experiment, just as relevant! We will use a golf ball and drop it into a pan of mud made from dirt in your area. We will measure how big a splash it makes! About as useful as measuring UV sensitivity of a crappy Geiger tube! Top quality Geiger tubes are metal and use a thin metal window for Alpha detection. Point: SAVE YOUR MONEY UP AND GET A PROFESSIONAL GEIGER TUBE! (if you are really interested in using a Geiger tube to measure radiation.)
99% of the counters that people buy, use these [quote] 'crappy' glass tubes. So far I have been sent over two hours of video footage, from people who are truly interested in knowing more about this subject. Personally, I would not waste MY money on an expensive GM tube, just because it can measure some higher energy alphas, it suffers from the same main issue as any other GM tube, the inability to compensate for energy. For the cost of just the professional Geiger Muller tube, people can buy a complete gamma ray spectrometer. BTW, energy compensated tubes are only x/gamma tubes. Understanding why effects like this happen is not irrelevant, at least not the many people who have shown interest in participating in this experiment. Just buying a more expensive piece of equipment does not give a deeper understanding of the subject, whereas figuring out the limitations of inferior equipment can yield some real insights.
@@project-326 Until you use some really capable INDUSTRIAL QUALITY equipment you don't get a real picture of what can be done. These junky geiger counters are TOYS that kids use to play around. Your comment on the sterilizing wand "piece of snake oil" can be accurately applied to these cheap junk geiger counters. Industrial spectrometers do NOT use geiger tubes!
sorry, I'm having trouble seeing the trajectory of this argument. Initially you criticized cheap tubes and praised expensive alpha capable GM tubes, but both have the same issues, an absence of energy compensation. Being cheap doesn't make it worthless - with a deep enough knowledge of the subject, you can extract a lot of good quality data from a basic GM tube equipped counter. Often it is not the quality of the tools but how you use them that makes the difference. Cheap tools require more intellectual capital to be applied. Yes, there are extreme cases where this argument breaks down... On another topic, I follow your channel quite often and my young daughter asked me "Daddy, how can we make a light bulb", well I'm kinda screwed now, Daddy MUST have an answer. My first attempts were quite poor - what kind of torch would you recommenced for a beginner to that subject? I used a MAPP gas torch with very horrible results, maybe mine was too cheap ;-)
@@project-326 Into the search bar look for "glass blowing tools." Much more experienced people than me have advice. Be sure to separate them into "professionals" and hackers. (like me!)
Why not use the huge spherical UV source in the sky? Outdoor light may effect things. One can also make an HV probe out of a single 1 gigohm resistor with 1% tolerance. It becomes a little better for direct-reading... so that 0.415v on the display is indicating roughly 415v. Give or take a bit but close enough. The 1 gig resistors are not cheap but Digikey and others sell them. Be sure to get 1% tolerance/accuracy. Can put them inside the shell of a ballpoint pen for a neat little HV probe.
You are right about the sun, but I live in the tropics and right now we are in the early monsoon season, so the sun it not all that visible. The other issue is that I make this videos in my spare time, ie mostly at night... Don't worry about the tolerance of the 100M resistor, it you perform a calibration as shown in the video then the errors get removed.
Thanks for the mention sir ! really appreciated! That may be off topic but the counter we have for Alpha and Beta made by Tennelec, use a methane/Argon mixture. This is an interesting experiment! I will try it and get back to you! I have an old UVC lamp I can dig up.. I must admit, you are doing everyone interested in the subject a very valuable service ! We should all be grateful for your content, Thank you for doing these reviews and experiments! This channel will go far for sure!
I really look forward to your results, as I am sure many of the viewers are too.
@Neptunium I'm sorry, but from now on, you shall be called Uncle Rick as an inside joke (if you're fine with it, of course)
right now, in alternative reality, something bad might be happening to an alternative version of you, we must be careful what we say to Uncle Ri... I mean Neptunium!
@@project-326 lol! No I don't mind! Believe it or not I've never seen the show!
@@Neptunium OK, so which version of you just answered? I have only watched a few, but I you want the gist, start at the beginning S1E1...
I look forward to a teardown and analysis of the spectrometer that you use here. Thanks for all you do.
Your wish is my command. I'm actually working on that right now, stay tuned...
I was somewhat alarmed when my (un-cased) Geiger counter started going crazy when I took it outside on a sunny day. I eventually calmed down and put it down to either high humidity or the photoelectric effect and not a crazy radiation event.
I bet that was an interesting experience...
(one eyebrow raises) FASCINATING! Time to order some super high value resistors.
Awesome, everyone looks forward to your video results!
Absolutely love your videos, very educational and fun to watch.
I got a newer version of GC-01. It came with an unmarked tube that looked like the 613 junk. It was not as sensitive to the americium source as it should have been, but would go to alarm condition if the tube was exposed to sunlight through a window. I live in Florida and the UV index was high in summer when I did this. A lot of the UV gets through the glass windows then.
I replaced the GM tube with a J321 and it worked similar as it should to the americium source. It did not react at all when directly exposed to sunlight through a window like the previous GM tube. I measured the voltage using a divider circuit similar to your experiment, and measured 525 volts. I was surprised at the voltage because the load resistor was 8.3 Meg Ohms. I did not change the load resistor because the unit works great as far as sensitivity to radiation goes.
The newer unit came with a 300 MAH battery which was a ripoff (I replaced it with a 1,100 MAH battery). It also has no backup battery, a USB that only charges the battery, and a smaller speaker/buzzer.
The only positive aspect is: It is very easy to make the unit click on radiation counts. There are two resistors on the circuit board right next to each other (R16 and R36). R36 is the load resistor for the speaker/buzzer, and R16 is the load resistor for the LED on the other side of the circuit board. If you solder a tiny piece of wire between the upstream side of R16 and R36, the unit will click with a neat sound. Also when in alarm mode you can hear the clicks and the alarm tone. No resistors or capacitors required.
Great feedback, sadly this manufacturer is on the race to the bottom, they have just released the GC-02 which has all of the most terrible permutations that they have tried on the GC-01, combined into one product.
Adi makes a ,140v opamp, arranged for higher voltage. If you tickle the dragons tail, pre ionization you can take an ac coupled reading. Perfectly flat and you can distinguish the particle energy and light. It will measure vibration too. A neon bulb will work also. Not to mention adapting to different tubes.
that sounds like a really interesting project. DO you mean running the tube in the proportional region of its response, at lower voltages?
@@project-326 Running it on a current source. You won't need damping gases. I think this may be the way the tube is driven now. It wouldn't surprise me. The variation in applied voltage used to maintain constant current represents energy added externally. A drop in voltage indicates applied energy.
But the voltage would try to rise to absolutely tremendous levels if you drive one from a pure current source. Between ionization events, the current is very close to zero. The tube is not a simple resistive load.
With GM tubes, it is better to think in terms of charge instead of steady state currents. For accuracy, the tube voltage needs to be maintained within the Geiger plateau and that is why constant voltage supplies are used.
The anode resistor does add some passive external quenching, but to stop the avalanche traveling the full length of the tube and further increasing the dead-time is what the quenching gas does. There are also active quenching systems (very high end) that actively pull the anode voltage down in a very short time after each activity, but I don't know of any commercial tubes that omit the quenching gasses altogether...
@@project-326it must be the same as a neon bulb. when you drive a neon bulb with a constant current it makes a radiation detector. Also you can measure vibration into hundreds of kilo hertz. Plus visible light. Anything to trigger excitaton will be compensated by the constant current source which manifests as a drop in voltage, which is your signal.
Again a very interesting and informative video. Thanks! I will try to do the UV experiment with my FS-5000, but it might take a while.
take your time, all input is very gratefully received...
I´ve created this user and youtube channel just to share my results, as links are problematic. Thank you for your amazing research and videos. My video with results is already there. I´ve posted other comment on the community Studio 326 section .
This is fantastic! Wow, the voltage is super high, way beyond the plateau. The Helium/Neon tube discharges give a nice color, don't you think? What YT profile would you like me to credit with this?
@@project-326 Thanks! Now I know how difficult is to make a tiny simple video. Could be this one, who knows in future I post more videos will be on this account!
Abou the Helium/Neon tube discharges, when I saw that - Wow! That´s really nice, never have seen.
Oh man I gotta do this. Just ordering some resistors and an enclosure for them.
Thanks, I really look forward to seeing your results!
@@project-326 I mean, your project came just in time. Month back I was wondering that I should measure my CDV-700 output voltage. But now I also have a counter with J305ß tube connected to my smart home. So I've got the test subject freshly on hand.
@@project-326 Hmmm seems like this divider wasn't enough. Was able to make it and had a multiplier of 99.07. But for some reason my cheapo aliexpress geiger started counting like crazy, was able to measure voltage of 22,3V. Somethings wrong somewhere I guess
@@OH8EFI It can do that, usually the counting circuit is on the cathode. FOr the voltage measurement, it doesn't really matter if the tube starts counting.
Hi there. I understand the 100Mohm series resistor is to reduce the current when measuring the tube voltage, but am puzzled what the 1Mohm resister is for. (I’m a newbie in electronics). I wanted to also say thank you for this info, it’s very helpful, as I have recently purchased an old military dose rate trainer that uses a GM tube and am currently trying to fix it, and have been struggling to measure the tube voltage.
Also just wanted to say what a fantastic entertaining and informative channel this is, and thank you for taking the time to make these videos. They are all excellent.
First of all, a hobby channel, I really appreciate your nice words.
For the high impedance probe, the 100M resistor is to limit the current, as you already figured out, the 1M is for the multi-meter (DMM) to made a measurement against. Because the DMM typically has an input impedance of between 10M and 20M, the lower impedance will reduce the amount that the internal impedance will further reduce the measurement value by.
In theory, you can just add a high impedance in series to make this measurement, and that is also valid, so long as you calibrate the measurement system before us on a low impedance voltage source. The purpose of the 1M resistor is to try and get a measurement ratio that is around 100:1, it just simplifies the process when there are two known values.
That said, there is nothing wrong with just adding 100M in series with one of the leads of the meter...
Hi there. I measured the tube voltage on my Bosean FS-5000 using a 100M resistor in series with my Hantek DS02D15 oscilloscope, and it came in at 413volts rms. (Conveniently 120volts dc-rms=1.20volts dc-rms measured, so I figured 413volts=4.13volts measured) I hope my measurements were correct. I tried my cheapo UV flashlight and it had no effect. I will try to make a video at some point if I get the chance.
I also measured the tube voltage of my old military Geiger and only got 205volts which explains why it’s not working.
Love your videos. Please keep them coming
What an excellent bit of crowd science.
I have a dental "UV" curing wand that operates at 428-480 nm with 1200 - 1500 mW/cm² output. Although they are often called UV the wavelength is too long and more in the visible violet region but it's high power and possibly spreads into the UV. I found however this had zero effect on the J321 tube in my GC-01 unit even when held closely at the cathode end. I have another UV torch of unspecified output for curing mobile phone display glass adhesive and that had no effect either. Neither did a small UV keyring banknote checker. I went outside in the sunlight and perhaps that did have an effect but it wasn't that marked.
My J321 is being operated at 556V. I'm measuring with a x100 scope probe at the output of the voltage multiplier on the final capacitor C28 before the 2MΩ series limiting resistor R12 but despite this the voltage falls when the probe is first connected, to 516V due to the 100MΩ load and the effective impedance of the multiplier.
From what you say the working voltage is set too high. I am thinking of adding two series connected 200V zener diodes at this point to ground to lower and stabilise the applied voltage to 400V rather than rely on the dubious loading resistor R38 which is set too high anyway.
The GC-01 has almost zero voltage regulation so they added a loading resistor (or at least a pad for it). In the end, I went for a 20M loading resistor. Ideally the J321 should be working at 380V but most manufacturers try to push this to the top end to give a higher sensitivity, which is fine, if the voltage is well regulated...
Many viewers have found their own values between 5M and 20M to get the tube voltage correct. Just be sure to measure just the tube voltage without the anode resistor.
Thanks for the nice feedback!
:-)
@@project-326 I measured before the 2MΩ anode resistor on the capacitor C28 because the 100MΩ scope probe, when dabbed on instantly shows the full 556V stored on C28 which then exponentially discharges under the 100MΩ probe load to 516V. This can easily be captured on the scope and measured with the cursor. The initial 556V is also what I presume reaches the tube through the 2MΩ anode resistor when zero tube current flows (between clicks - confirmed by measuring across R12). If I were to measure directly at the tube after the 2MΩ anode resistor then because there is no capacitor to hold up the voltage, dabbing on the 100MΩ probe instantly divides with the 2MΩ resistor giving a false low voltage 100/102 x 556V = 545V which would then decay as C28 discharges but to an apparent lower 100/102 x 516V = 505V. Ok not a huge error of 11V and my scope probe will have a bigger error.
However, I've just now added two 200V Zener diodes effectively across C28 which has greatly stabilised the voltage. It doesn't now dip down when the 100MΩ scope probe is applied. It measures at 428V which seems higher than expected. I did try to calibrate my 100MΩ scope probe against a 100V lab supply which when checked against my multimeter seems to read +2% high and as the 200V Zeners can be +/-6% so could read up to 432V - so it's within credibility.
I also checked the supply current and it's unchanged which could have been an issue with pulling the multiplier down more but it seems fine. The units background reading seems to be unchanged.
did you notice any UV sensitivity before or after adding the Zener diodes? At background there will be very little difference, going from the middle of the plateau to the top of the range would result in about 5% increase in sensitivity, you would need to be able to average over a very long duration to be able to notice that...
The tube voltage seems to be very high for the J321, are you getting any visible ionization (you need to look in a dark environment to see)?
Well it was high at a measured 556V which is why I added the Zeners and now it's about 420V given my attempts to calibrate the x100 probe. I've never seen any visible ionisation even with the UV sources but they might all be on the longer side of UV.
it would be great if you made a quick video to show everyone what work you did, I will be sure to include it in the next video...
Well there goes my attempt to be anonymous on the internet. 🕵♂
Your video was very well received and made a huge difference to my thinking about this project. Thank you for agreeing to me sharing this, your contribution was very helpful.
Thanks!
I love your videos
thanks mate, appreciate the feedback!
Huh, just watching this video now. I just so happen to have a high voltage meter and real (higher frequency) UV pen light, along with the GC-01 that arrived today. It would be easy enough for me to test this, but making a video of it wold require a bit more work, since it's not something I typically do.
That's awesome. Don't forget the impedance issue - I used 100M/1M resistors in my probe to prevent the DMM impedance pulling the voltage down...
I'll probably nag you later about the video, just record something quick and leave it to me to do the editing etc...
;-)
@@project-326 Thanks. If I remember correctly, it has a high resistance option too. I'll check tomorrow and maybe get around to making a quick video too. Cheers.
@@project-326 It's going to take a little longer than I thought. The "secret" high resistance mode (holding down the Hz % button while powering on) on my 87-V doesn't seem to be enough. The voltage was still being pulled down to 2 hundred something. I was able to test that there was a bit of UV sensitivity if I held the light near the negative side contact on the side of the tube, but not much of a change other than that. This is with the updated third-party firmware though, so if you want the stock firmware (mine shipped with v1.6), I can flash that back onto the GC-01. Cheers
You were staring down the barrel of the ones that showed the most harder UV production. Do not look at UV sources, put something that fluoresces or trust your detector.
The camera was looking down the barrel... And I have good UV protection glasses.
Great video! Keep going and best regards :)
Great video!
I really want that spectrometer. Do you have a link to the Taobao seller please?
Found it. Link below but probably gets deleted by UA-cam...
[edit] Yup, they've deleted it. Imagine we could post a link in a comment, the horror! [/edit]
@@Ni5ei Hi! Can you, please, send me the link? Thanks!
I just added it to the video description!
@@project-326 The link provided appears to be for a $2 grow lamp.
@@Muonium1 Strange, I just tested and it works for me. Mind you TaoBao is only available in China so you might be getting redirected if accessing from outside.
Very interesting! Do you have a link for the optical spectrometer? Thanks.
I just added it to the video description!
@@project-326 How would someone in the USA order this?
@@gblargg I just opened it up, its basically a piece of DVD glued over an OV2710 camera module with a 3D printed chassis to hold everything in exactly the right place. The design is actually quite nice, clearly the guy spent a lot of time getting the design to be just right. It does say "DIY" on the TaoBao ad... It works way better than the one I made a couple of years ago...
I'm really not sure where you can get this in the US, there must be other folk doing something similar there?
@@project-326 That's actually inspiring, I didn't realize it was so easy. It sounds like that Theramino software for spectrometers is similar to sigrok for logic analyzers. I have one of those simple spectrometers you look through, with a diffraction grating. That would probably be easy to modify with a webcam.
@@gblargg I think that the time consuming bit is getting all of the alignments correct. For me, $49 is worth the time saved as I already have some other applications lined up for this device. I was actually surprised that I could perform some simple gas chromatography using this unit. It seems that the OV4710 camera module has a pretty wide spectral range, I think that the maker also removed the IR filter from the camera.
UA-cam deleted my link to the video. Both here and in the community. Well, I tried...
I know, YT can be a pain about links. Don't worry, I managed to grab the video - really nice work!
I am going to start on this project this week. I am a little bit late to the show but I will give my results. I have Crocodile clips (UK) Alligator clips(US) Gojira clips(JP) nipple clips (DE) GMC-300E+V4
Looking forward to the results!
@@project-326 My results from a GMC-300E-4V shrink tubed J-305 GM tube Powered the GMC300Ewith programmable DC pwr supply from 3.7v @800 ma to 9.1vdc @ 950ma. used 360 to 400nm UV light no excitation of tube, voltage at GM tube 410-411 VDC dropped to 408Vdc when excited by Thorium-232 source. My conclusion its, the Gas in the tube , its concentration and purity vary from tube to tube. I saved it all on video. How do I send you the video ?
@@huntingtimes7732 just save it on your channel and then let me know so I can get it from there.
@@project-326 I sent you the link on your community post channel thingy you can use and abuse it how ever you see fit !
You are one hero among mortals🤜🏻
I'm just a bloke that shines some UV light onto GM tubes and sees what happens...
:-)
I have a purple lazer pen. It illuminates LED lights. The lights all turn on . Some LEDS do nothing, others glow like the sun. If you twist the + and --- of the LED together , nothing happens. It doesn't light up afterwards.
Thanks for the idea - I took my violet laser and impressed the kids with a magic show, how I could make a white LED light-up in their hands without power!
;-)
After connecting my geiger to thingspeak and looking at graphs i noticed when my ws2812 led strips were on my j305 was reading very high. I ended up putting it back in its box for light sheilding. Is it only UV that effects tube? If so it confirms the ws2812 led puts off UV, This is something I have been wondering if they did since noticing the phosphor on a large cob led i have seems to glow yellow when under ws2812 lighting. Maybe ill make some vid's about it. Good channel keep up the good work.
if the voltage is high enough, pretty much any photons will cause triggering...
some of the tubes are uv sensitive and some are not. Also seems to be more near the anodes
What I am trying to test is the UV sensitivity mainly due to the tubes that are operating at the top of above the Geiger plateau range. It is common for manufacturers to have the tube voltage set high as it gives the impression of higher sensitivity. So far the results I have received seem to confirm that this is the case...
Looking at the physics of a typical J321 tube, if the tube is being operated in the middle of the Geiger region, then in order to cause an ionization event from the photoelectric effect would require photons that are in the extreme UV range (
@@project-326 ahh sorry yeah manufacturer GQ electronics has started putting black sleeves over tubes to prevent any sensitivity. Sunlight is also a factor. I've brought one of these tubes in the sunlight with i assume overvoltad meter. and had it go crazy Also, do you have any source of directly talking to you as WeChat or Telegram
i have an entire box of UV LEDs, a multimeter, and i've ordered a geiger counter :)
That's awesome news! Do you have 100 M resistors?
@@project-326 yeah, i've got both :)
@@project-326 i don't have 100MΩ resistors, but i did an adjusted version of your experiment using a resistor divider with a 10MΩ and a 100kΩ. its dose rate alarm went off when probed (in the graph this reached 10kcpm), but i measured 3.03V which translates to 316.1V on the tube itself.
device: FNIRST GC-01 (flashed with RadPro firmware)
tube: J613
measured resistor values:
Resistor 1: 10.29MΩ
Resistor 2: 99.59kΩ
uv led test (using 6 uv leds):
there were no extra clicks detected, even while the uv leds were directly focused on the areas shown in video.
@@ThatJay283 Just as an experiment, try putting 10 x 10 M resistors in series, I think you will find that the measured value you get will increase.
@@ThatJay283 Thank you for taking part in this experiment! Perhaps you can put 10 x 10M res in series? The main issue is that a 10M resistor will load the tiny HV power supply and pull the voltage down, hence the voltage you will read will be lower than the tube will normally be working at.
Thanks!
I popped open a GMC-320+ V4... The tube has a heavy black plastic optical shroud, Shining my 365nm torch into the small exposed glass sections at each end didn't materially change the click rate... might look at probing the voltage later.
quite a few manufacturers are also still under the impression that UV sensitivity is from the tube and often use a piece of heat-shrink tube to cover it. I just cut mine off.
Why do you need to make this voltage divider when your AVO meter is rated for 500V (or 1000V)?
Presumably the typical 10 meg ohm of input impedance on a multimeter is way too low to have in parallel with the tube being similar in size to the anode resistor of the counter.
Because of the internal resistance of the measuring device, which loads the high -resistance voltage on the meter tube too much and therefore causes it to break down. A normal multimeter that measures up to 1000 volts has 10 MOhm internal resistance. With an anode resistance of 5 MOhm in front of the counting tube, the voltage collapses on 2/3. Sometimes the high voltage generator does not even manage to provide the flowing current of >20 µA.
To use an Highly-Impedanced voltage divider is completely correct.
@@dg0mg Got it, thank you.
As other viewers have pointed out, its not a voltage rating issue. Some of the power supplies used on these devices can only source a few microamps of current, the GC-01 is a classic example. Normally a DMM has an input impedance in the region of 10 MOhms, so making the measurement actually changes the voltage level by a significant amount.
Anyway, thank you for the comment, this channel is dedicated to learning so there are no dumb questions, please keep asking questions!
I think you need to remove the white protection Tape/Paper first!! from the black box spectrometer before using it!! 🤔🤷🏼♂️
it is a diffuse filter, it even came with a wad of those too.
@@project-326 then what is it made of?! Because a lot of materials directly absorb UV radiation! There are only a few things that are transparent for short wave UV-C radiation!! Like quartz glass!! 🤷🏼♂️
@@project-326but I Do want to thank you for your work! You are helping the GM community a lot in general!! 👍😉
@@TheOpticalFreakThe spectrometer doesn't claim it can measure UV-C. UV-C is 200-280nm, UV-B is 280-315nm and UV-A is 315-400nm. The spectrometer can only measure from 300nm upwards.
I got so much interest in that cheap optical spectro, that I am now making a video all about it. Stay tuned!
An ozone producing mercury vapor tube will drive these tubes crazy.😂
I recently tested a GTL3 type UV mercury vapor arc tube, the glass of the GM tube and the ITO coating seems to block the UVB and UVC.
gd work
I do hope that you will be able to contribute to the project?
I have several mica sensors. I do not know if ultraviolet light passes through mica...
I would doubt if any light can pass the mica...
@@project-326 Why is that? You yourself show such a sensor at 4:02 Through mica you can see the inside.
I tried on my pancake mica tube and UV made no change in count (quick high-impedance probe gave 430V on tube). Still going to post something.
@@gblargg Thanks, I look forward to the experiment video!
Если видео сняты в 4к то почему ролик в 1080p?
I usually record at 4K (I just use a cell phone camera, nothing special) so that when it gets transcoded back down to 1080p, less image quality is lost. I also helps in post processing, cropping the image won't have too much effect on the final result...
@studio326- Don't forget youtube compression
your are so right about that. YT seems to have their own video compression algo for storage and it works well on some parts of each video and is pretty terrible on other parts.
@@project-326 By the way, I just trusted my Bosean fs5000 and its tube reacts to 365nm ultraviolet.
Let's do another experiment, just as relevant! We will use a golf ball and drop it into a pan of mud made from dirt in your area. We will measure how big a splash it makes! About as useful as measuring UV sensitivity of a crappy Geiger tube! Top quality Geiger tubes are metal and use a thin metal window for Alpha detection. Point: SAVE YOUR MONEY UP AND GET A PROFESSIONAL GEIGER TUBE! (if you are really interested in using a Geiger tube to measure radiation.)
99% of the counters that people buy, use these [quote] 'crappy' glass tubes. So far I have been sent over two hours of video footage, from people who are truly interested in knowing more about this subject.
Personally, I would not waste MY money on an expensive GM tube, just because it can measure some higher energy alphas, it suffers from the same main issue as any other GM tube, the inability to compensate for energy. For the cost of just the professional Geiger Muller tube, people can buy a complete gamma ray spectrometer. BTW, energy compensated tubes are only x/gamma tubes.
Understanding why effects like this happen is not irrelevant, at least not the many people who have shown interest in participating in this experiment. Just buying a more expensive piece of equipment does not give a deeper understanding of the subject, whereas figuring out the limitations of inferior equipment can yield some real insights.
@@project-326 Until you use some really capable INDUSTRIAL QUALITY equipment you don't get a real picture of what can be done. These junky geiger counters are TOYS that kids use to play around. Your comment on the sterilizing wand "piece of snake oil" can be accurately applied to these cheap junk geiger counters. Industrial spectrometers do NOT use geiger tubes!
sorry, I'm having trouble seeing the trajectory of this argument. Initially you criticized cheap tubes and praised expensive alpha capable GM tubes, but both have the same issues, an absence of energy compensation. Being cheap doesn't make it worthless - with a deep enough knowledge of the subject, you can extract a lot of good quality data from a basic GM tube equipped counter. Often it is not the quality of the tools but how you use them that makes the difference. Cheap tools require more intellectual capital to be applied. Yes, there are extreme cases where this argument breaks down...
On another topic, I follow your channel quite often and my young daughter asked me "Daddy, how can we make a light bulb", well I'm kinda screwed now, Daddy MUST have an answer. My first attempts were quite poor - what kind of torch would you recommenced for a beginner to that subject? I used a MAPP gas torch with very horrible results, maybe mine was too cheap ;-)
@@project-326 Into the search bar look for "glass blowing tools." Much more experienced people than me have advice. Be sure to separate them into "professionals" and hackers. (like me!)
Why not use the huge spherical UV source in the sky? Outdoor light may effect things. One can also make an HV probe out of a single 1 gigohm resistor with 1% tolerance. It becomes a little better for direct-reading... so that 0.415v on the display is indicating roughly 415v. Give or take a bit but close enough. The 1 gig resistors are not cheap but Digikey and others sell them. Be sure to get 1% tolerance/accuracy. Can put them inside the shell of a ballpoint pen for a neat little HV probe.
You are right about the sun, but I live in the tropics and right now we are in the early monsoon season, so the sun it not all that visible. The other issue is that I make this videos in my spare time, ie mostly at night...
Don't worry about the tolerance of the 100M resistor, it you perform a calibration as shown in the video then the errors get removed.