Power a 12-volt relay directly from 230VAC mains voltage
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- Опубліковано 29 вер 2024
- If you need a 230V relay, but all you have is a 12-volt relay. No problem build the simple circuit to drive a 12-volt relay directly from mains voltage! No 12 volt power supply required. All you need is 4 diodes and a capacitor, to convert a 12-volt relay to a 230-volt relay.
Greetings from South Africa - hope you are getting used to all the rain I hear in some of your videos - enjoying your videos - what is the 3 in line connector you are using to connect mains in this video?
@@michaelstolman536 it's some type of Chinese WAGO clone. But wago don't actually make a 3 inline version like that. I find them quite useful. I got them from ebay.
Good work brother ❤ that so useful
Neat. Just bear in mind these caps can fail short and it will likely won't trip the breaker right away with relay coil resistance of several kOhms and may cause fire.
I suppose you can always add a fusible resistor. Like the ones they have in the LED lamps with cap droppers. Metallized film capacitors generally do not fail short-circuit. They have "self-healing"characteristics. During self-healing events, they end up losing some of their capacitance over time. So with overload voltage spikes and fault conditions they become more "open-circuit" overtime. Electrolytic capacitors definitely fail short circuit! quite violently sometimes.
What's the point without any values!
The capacitor value will depend upon the type of relay you use. It will be different for different types of relays. Just do some experiments.
Everything was in hand, all that was needed was the details of what's used.@@MyProjectBoxChannel
thank you brother that's so useful
Will it be better if the output of the bridge rectifier is filtered with an electrolyte capacitor?
Yes it would give you smooth DC, but the relay works fine with unsmoothed DC. I wanted to keep the circuit as simple as possible. You could also add a zener diode to regulate/clamp the voltage, but this would add extra complexity to the circuit. It's a simple circuit and it works great👍, but you need to match the capacitor, to the coil impedence, to drop the correct voltage.
Simply just use a 1k resistor
It will get very hot dropping that much voltage! Using a resistor is terribly inefficient. But a capacitor can drop AC voltage efficiently, without generating any heat😉👍
how abaout drive a mosfet?, its relay coil make difference output?
Value or marker/code of capacitor?
The value of the capacitor will depend, on the impedance "AC resistance" of the relay coil you are using. I would start by using a 470nf (400v) capacitor. Measure the voltage on the coil, and if the voltage is too high, lower the value of the capacitor. If the voltage on the relay is too low, increase the value of the capacitor. If you are using a 12-volt relay, 10 - 14v is acceptable.
Es genial, es lo que necesito encontrar
Nice, will it be reliable for a long run?
Sir I use transformer less 12v power supply but 1 prob my fiter cap heat up
Many thanks.
Why you dont discripe how to calculate the cap?
By the way ... "save to use" is a phrase you dont find here 🎉
I think the voltage separation between the coil side and the switch contacts is very good. Film capacitors don't generally fail short-circuit. In fact, they can lose capacitance over time, as they "self heal" ( a short-circuit will blow itself clear)
@@MyProjectBoxChannel we in Austria Europe we learn in the electronic school to avoid this Type of Design. We learn to use galvanic isolated Designs, But they are to complex and Not a quick solution. Like your idear. Your dirty Design have a big plus. If Something Blow Up, the hole Design Blow Up. I think your Design Work also with one Diode and two Caps. Relays are Not realy fast and 50-60hz is easy to Puffer also with only one Phase of the sinus. I Like your idear. I have also more 5V and 12V Relais at Home.
@@NetrunnerAT I tried using just one diode, but it doesn't work 😩. The capacitor just changed up with the half-wave DC, and it won't work as a capacitive dropper. You might like this circuit. ua-cam.com/video/oBR5O391m_c/v-deo.html
@@MyProjectBoxChannel ah thx ... Yes ... I See ... Make Sense.
where can i find this relay.
You don't need to use this specific relay. Any 12v-24v relay will work. It's also possible to selvedge this relay from old PCBs and old appliances. I have seen similar relays on ebay and online aswell.
@@MyProjectBoxChannel ok bro