Tagged Questions

6
votes
2answers
187 views

Switching Between Two Voltage Supplies

I have been trying to work out a circuit something like the following: simulate this circuit – Schematic created using CircuitLab I want VOUT to be 3V when the switch is open and 5V when ...
4
votes
1answer
363 views

Do I need a protection diode here?

Here I have an automotive relay (from a scan of a workshop manual I'm afraid) which is rather more complexly wired up than the relays I'm familiar with. In this diagram: L/Y - +12V L - From the ...
2
votes
3answers
803 views

What kind of diode to use with ADC inputs

I am looking for diodes to protect my ADC from over voltage conditions. From what I have researched so far, I know that I need schottky diodes hooked up from the input to the ground and the input to ...
3
votes
3answers
2k views

What happens after a zener diode breaks down?

I've strapped a 6V zener diode across the 5V/GND rails of my circuit, and I want to know what will happen if my supply were to somehow fail pass 12V straight to the rest of my board. The zener will ...
2
votes
1answer
493 views

Using Zener diode for circuit protection on RS-485 network

I'm examining an RS-485 driver circuit that uses what look like Zener diodes between D+ and gnd and D- and gnd. Anode is connected to gnd, cathode to the D+ or D-. So in this arrangement the idea is ...
3
votes
2answers
775 views

Is a protection diode needed on a TRIAC optocoupler and what for?

Please refer to page nine of the Sharp S108T01 / S108T02 datasheet: Is this diode needed - why/why not? How do I choose the correct diode, if yes? UPDATE: Thank you all for your educational ...