Awesome! Thank you for sharing your annotated schematics. I'll be adding them to my PET repair binder.

Excellent video and explanation on the PET power supply. Looking forward to your next video!! Thanks for sharing

that's pretty weird to have stuff connected to chassis protective ground, but different times i guess

@HutchCA

8 ай бұрын

It's not just a protective ground, it's also the neutral reference point for all the voltages.

@lasskinn474

8 ай бұрын

@@HutchCA still weird. so no current passes through it?

@HutchCA

8 ай бұрын

@@lasskinn474 No current should be passing to earth, the mains current travels between hot and neutral. Neutral is normally connected to ground at the service panel. The chassis ground is there to protect you if a plug is wired wrong with the hot & neutral backwards. In that case the hot wire would be connected directly to ground providing an preferred current path so it doesn't go through you to ground. The transformer isolates the AC so that on the low voltage side, there is no neutral, current only travels through the secondary windings equally. It's normal for the "ground" on a PCB to be connected to the chassis ground. The PCB ground does have current flow since it's effectively the negative "source" for the DC current. Depending on your logic, you could call the "ground" negative -5V and call the +5v rail ground.

@lasskinn474

8 ай бұрын

@@HutchCA I'm from europe where everything is designed so that you can insert the plug either way (and the protective earth is just an extra protection in case something inside a machine electrifies the outside of the machine the breaker would pop), so it still sounds a bit weird(to me). (and for center taps for amps or whatever you don't need to do that either)

@HutchCA

8 ай бұрын

@@lasskinn474 Ahh, yes. For 240 volts, there is no neutral, there are two hot wires. In the US it's 120V +120V = 240V, OR 120V + Neutral = 120V The earth connection does the same, in case either one of the hot wires comes in contact with the metal chassis, it will go directly to ground and not via You. But under normal conditions, there should be no current path to earth.