6:39 that's a very accurate analogy! The current "flow" on a capacitor happens literally across 2 plates, when 1 charge gets to one of the plates it repels another on the other plate, when that first plate is "full" it can no longer push other charges, and it stops current flow, it's almost literally as if it's a bridge and it's been blocked off.
Saw you mention this on Mastodon and I finally got a chance to watch. This is awesome! I love the idea of explaining what you think you know as you're learning it. Your explanations are clear and straightforward, and I think this hits exactly the sweet spot of extrapolating and experimenting, but also being honest and direct about what you don't understand. I took up electronics as a hobby a while back, and was fun retracing some of those early steps trying to wrap my head around these building block components. I was interested in this stuff as a kid, but I could never quite understand these analog components, especially without web sites and UA-cam. I'm trying to resist the urge to jump in with a bunch of nerdsplaining, especially since I'm far from an expert. It sounded like you were interested in feedback, so I'll just mention one or two things: The capacitors dotted all around circuits are often for "decoupling". Logic circuits are constantly switching on and off, changing their load on the power supply. Because of resistance inherent in the circuit traces, internal to batteries, etc., that power can't be delivered everywhere instantaneously. That results in switching noise, where if you looked at the voltage with an oscilloscope, you'd see it's not a steady 5 volts, but full of spikes and ripple. And more immediately, the part that just switched on will see a voltage sag as it tries to use more current. That can be enough to cause it to malfunction, especially with higher-speed chips. So a capacitor is placed, not in series but in parallel, close to the chip's power pin. They have the effect of filling in for the power supply and smoothing out that transient, even if it's only nanoseconds. And the physical size of those type of resistors is usually connected to how much power they can dissipate. Those look like 1/4 watt. The other common size are the little 1/8 watt ones. For digital logic circuits, it's rarely important, and I've gotten used to not thinking about it.. until one goes up in smoke. Looking forward to more of these!
Awesome, thanks for this! I've noticed on many boards (by way of watching retro computing stuff on UA-cam), that it seems pretty common to have one capacitor per IC - so that explains why! I guess by way of analogy, those capacitors are sort of acting like a coral reef or an atoll which can protect/shield an inner lagoon from the ocean's big waves? Or maybe a better analogy are the baffles they put inside of water tank trailers and whatnot to prevent the liquid from sloshing so much when the vehicle changes speed or goes around corners? (Although the mechanics of this is probably really different for electricity. I think baffles and reefs are basically just breaking the waves and restricting motion but a capacitor stores a charge and then releases it back in, I guess, but in my head I see this as sloshing back and forth like liquid in a tank, so maybe it works?)
I guess it would be more like a small reservoir/tank? To really strain the analogy, I guess it could be seen like you have some machine that suddenly demands water, and the main pump is on the other end of a long pipe. When it starts sucking on the pipe, the first thing that happens is the pressure drops and it doesn't get enough water, so you have this charged-up local supply that can make up that pressure for a few seconds. However my brain is wired, analogies don't work very well and tend to confuse me more than help me to understand things. I'm aware the water analogy for electricity is very popular and works for the vast majority of people, I just tend to avoid it. My way of thinking is that it's acting like a capacitor: it charges up to the supply rail voltage and when a transient pulls the rail down, it discharges to bring it back up. That's probably not super accurate either, but in practical terms when you're designing a circuit you just look at the manufacturer's data sheet and they tell you what to do (e.g. page 13 of www.ti.com/lit/ds/symlink/sn74hc04.pdf?ts=1701017669732).
6:39 that's a very accurate analogy! The current "flow" on a capacitor happens literally across 2 plates, when 1 charge gets to one of the plates it repels another on the other plate, when that first plate is "full" it can no longer push other charges, and it stops current flow, it's almost literally as if it's a bridge and it's been blocked off.
Saw you mention this on Mastodon and I finally got a chance to watch. This is awesome! I love the idea of explaining what you think you know as you're learning it. Your explanations are clear and straightforward, and I think this hits exactly the sweet spot of extrapolating and experimenting, but also being honest and direct about what you don't understand.
I took up electronics as a hobby a while back, and was fun retracing some of those early steps trying to wrap my head around these building block components. I was interested in this stuff as a kid, but I could never quite understand these analog components, especially without web sites and UA-cam. I'm trying to resist the urge to jump in with a bunch of nerdsplaining, especially since I'm far from an expert. It sounded like you were interested in feedback, so I'll just mention one or two things:
The capacitors dotted all around circuits are often for "decoupling". Logic circuits are constantly switching on and off, changing their load on the power supply. Because of resistance inherent in the circuit traces, internal to batteries, etc., that power can't be delivered everywhere instantaneously. That results in switching noise, where if you looked at the voltage with an oscilloscope, you'd see it's not a steady 5 volts, but full of spikes and ripple. And more immediately, the part that just switched on will see a voltage sag as it tries to use more current. That can be enough to cause it to malfunction, especially with higher-speed chips. So a capacitor is placed, not in series but in parallel, close to the chip's power pin. They have the effect of filling in for the power supply and smoothing out that transient, even if it's only nanoseconds.
And the physical size of those type of resistors is usually connected to how much power they can dissipate. Those look like 1/4 watt. The other common size are the little 1/8 watt ones. For digital logic circuits, it's rarely important, and I've gotten used to not thinking about it.. until one goes up in smoke.
Looking forward to more of these!
Awesome, thanks for this! I've noticed on many boards (by way of watching retro computing stuff on UA-cam), that it seems pretty common to have one capacitor per IC - so that explains why!
I guess by way of analogy, those capacitors are sort of acting like a coral reef or an atoll which can protect/shield an inner lagoon from the ocean's big waves? Or maybe a better analogy are the baffles they put inside of water tank trailers and whatnot to prevent the liquid from sloshing so much when the vehicle changes speed or goes around corners? (Although the mechanics of this is probably really different for electricity. I think baffles and reefs are basically just breaking the waves and restricting motion but a capacitor stores a charge and then releases it back in, I guess, but in my head I see this as sloshing back and forth like liquid in a tank, so maybe it works?)
I guess it would be more like a small reservoir/tank? To really strain the analogy, I guess it could be seen like you have some machine that suddenly demands water, and the main pump is on the other end of a long pipe. When it starts sucking on the pipe, the first thing that happens is the pressure drops and it doesn't get enough water, so you have this charged-up local supply that can make up that pressure for a few seconds.
However my brain is wired, analogies don't work very well and tend to confuse me more than help me to understand things. I'm aware the water analogy for electricity is very popular and works for the vast majority of people, I just tend to avoid it. My way of thinking is that it's acting like a capacitor: it charges up to the supply rail voltage and when a transient pulls the rail down, it discharges to bring it back up. That's probably not super accurate either, but in practical terms when you're designing a circuit you just look at the manufacturer's data sheet and they tell you what to do (e.g. page 13 of www.ti.com/lit/ds/symlink/sn74hc04.pdf?ts=1701017669732).
Learning doing things is the best way. I'm not from Mastodon, came here from YT related. If can I help in anything, please let me know.
Mastodon users unite! There are sub-dozens of us!