Re: PMOS in parallel with NMOS

On May 7, 9:59 am, Tomás Ó hÉilidhe <t...@xxxxxxxxxxx> wrote:
On May 7, 1:27 pm, rickman <gnu...@xxxxxxxxx> wrote:

Your idea won't work with bi-polar transistors. They turn on at 0.7
volts on the base.

I put 5 V on the base and 0 V on the emitter for the NPN.
I put 0 V on the base and 5 V on the emitter for the PNP.

I have no idea what you are talking about. Does your circuit only
consist of the transistors and a power supply??? What you have just
described will blow the transistors. The B-E junction will only
support about 0.7 volts. Trying to put 5 volts on this junction will
burn up the transistor.


There is no voltage you can use that will turn
them both off.

I set the microcontroller pin as an input, this will turn them both
off. (I've already tested it and it works) :-D

Ok, maybe it does if you use the transistors in a follower
configuration. But the forward voltage spec of the LEDs is loose
enough (depending on the exact model you choose) that you can't
guarantee they will be off in all situations. What you are really
doing is using the B-E junction as a diode for the voltage drop...
which is what someone told you to do. Can you explain how your
circuit works??? Do you understand it???

You consistently ignore principles of of good design and jury rig
things. I don't know if you are learning anything or not. Or are you
trying to learn every method that you shouldn't use?
.

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