Base of transistor HIGH without input

Question

I'm having trouble with a simple AND gate, using two 2N2222 NPN transistors:

For some reason, the base of the second transistor is high at 2.9V and I don't know what's causing this. I have verified that it isn't shorted to 3V and cut off the input to B so it seems the transistor is outputting the current. What could be causing this?

Is that your entire circuit? Is there anything attached to A, B or Out? — Colin, Jan 29 '19 at 15:43
A is attached to one of the inputs in a XOR gate, disconnecting it made B low. Out is attached to one of the inputs of an OR gate. — Karol, Jan 29 '19 at 15:49
I pointed this out obliquely in [an answer to this question](https://electronics.stackexchange.com/questions/418908/and-gate-made-out-of-transistors-letting-current-pass-despite-only-one-input-hig), but let me be more pointed: that's really not a practical circuit to be using for a gate. What are you trying to accomplish by going down this path? — TimWescott, Jan 29 '19 at 15:52
Were you letting input B float? How were you measuring it? Was your output high? Have you verified that you haven't damaged your bottom transistor in your experimentation? Have you verified that you don't have some other circuit flaw (if you have a plug-in proto board, pull that transistor and see if B is still high -- if it is, you have a flaw in your wiring scheme or your proto board). — TimWescott, Jan 29 '19 at 15:54
Your complaint is that B is at 2.9V, but what would you expect it to be? — marcelm, Jan 29 '19 at 15:55
If I connected B to ground, wouldn't that short the power supply? — Karol, Jan 29 '19 at 16:04
@Karol It does NOT matter what you measure on either A or B input ...they are inputs for your logic. holding A or B low will simply reverse bias the respective transistor holding it OFF. You are seeing problems where they do not exist. — Jack Creasey, Jan 29 '19 at 16:22

Base of transistor HIGH without input

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