Description:
1. PI-GPIO1, PI-GPIO2, PI-GPIO3 all control some load. I've made sure that the load current demands are within relay specifications
2. Relays' current draw range from 26mA to 40mA. The NMOSFET in the schematic can easily handle this current
3. I have one 120VAC to 5VDC that acts as voltage and current source all the NMOSFETS. Max current supported by this module is 600mA
4. I have current limiting resistor and pull-down resistors in front of Gate
5. The parts used in schematic are actual parts I intend to use.
6. Not a high performance circuit. Just turn on once and turn off after few minute -- no switching involved. I'm able to get away with using some ballpark numbers for resistors.
Questions:
1. Do I need to add a resistor in front of PI-GND to make sure I don't try to sink more current then what the GPIO can handle?
2. Will I run into any issues connecting -VOUT to Pi-GND ? This is my biggest concern. Kind and helping people on this forum have tried to explain that won't be any problem. But I haven't exactly understood why it's not an issue. if -VOUT provides a path of high resistance relative to PI-GND, wouldn't the current take the path of least resistance and just end-up going into PI-GND.
3. Lot of PCB through-hole wires and solder will be exposed on the bottom side of PCB (mostly worried about the AC lines). Are there any clean ways of isolating this exposed wires on the bottom of the PCB? My current solution is to just multiple wiring insulation tapes. It'll be good to have a clean solution to this problem
4. Any other words of wisdom/advice from experienced circuit designers.
Truly appreciate the help. Thanks in advance.
Statistics: Posted by microberry — Sun Aug 25, 2024 4:44 am — Replies 12 — Views 190