Finally…I cannot guarantee this will work, but I do not see anything definitely wrong with this small portion of the schematic.
I do not know what sort of signal is coming into R3 (or what is driving it) but you might want to connect another resistor from base to emitter of Q1.
If the MCU output is push pull as they often can be, then this won’t been needed.
Your symbol of q1 has at least some of its pins set to electrical type “unspecified” which always results in an ERC error. See Electrical type of schematic symbol pins (KiCad 4 and KiCad 5)
@Rene_Poschl I read your article on the pin types but I was still unsure with how to label the Transistor pins when used as a switch.
I finally was able to get the ERC issues to resolve by setting the Transistor pins as follow (I’m not sure if this was correct however!):
Pin 1 - Output
Pin 2 - Power Input
Pin 3 Open Collector
Does this seem correct?
Thanks again!
I looked at some transistors in the library and generally B is input, and E and C passive. Remember the classification has to take into account the configurations the device can be used in, i.e. common (emitter, base, collector).
Yes that is why I was not too forceful in my wording. It is almost free to include the pads for the added base-emitter resistor on the pcb (possible exception of a little bit of space) and you can always leave the component location unpopulated if desired.
This has become a long conversation. The pcb view shown earlier by scampa123 shows what look like some unnecessarily thin traces. I usually like to use traces as wide as can easily fit. Wider traces reduce stray inductance, are less susceptible to accidental damage, and of course are suited to higher current. There are exceptions for impedance control (I have not done that) or rarely where stray capacitance is an issue. But I doubt that either of those situations apply in this case.
Thank you to everyone for their input and feedback. I’ve re-written both of my boards schemas and designed two different boards which have been sent to OSHPark.
I’m anxiously awaiting their arrival to see if everything works!
Thank you again!!
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