Unable to drive 2n2907 transistor

Using Arduino Installation & Troubleshooting
#1

I am having problems getting my board to drive a 2n2907 transistor and could use some ideas from the community.

First, if I simply run the board bare, this gives me roughly 5-Volts on pin A7:

void setup() {
	pinMode(A7, OUTPUT);
	digitalWrite(A7, HIGH);
}

and this gives me 0.001V on pin A7:

void setup() {
	pinMode(A7, OUTPUT);
	digitalWrite(A7, LOW);
}

I have also tested the above on pin D13 with the same behavior.

I have a PNP transistor 2n2907 that I can manually drive without any issues at +5V on the collector if I use a 1kohm resistor on the base, connected to ground. The problem is that once I connect it to the arduino board on, I am unable to drive the transistor with any measureable change I cannot turn the transistor on or off - it simply floats its emitter, and shifts roughly 0.2V between being pulled high and low through the Arduino. This simple test doesn’t work to turn the transistor on.

void setup() {
	pinMode(A7, OUTPUT);
	digitalWrite(A7, LOW);
}

Is there something that I’m doing wrong here? Thanks in advance!

#2

If this is a pro mini, you cannot use A6 or A7 as outputs.

.

#3

larryd:
If this is a pro mini, you cannot use A6 or A7 as outputs.

.

Nano board - I believe A0-A7 should all be usable.

I still experience the same issue on D13, which is commonly used in example projects online.

#4

A Nano uses the same controller chip as a pro mini, A6 and A7 cannot be used as outputs.
Atmega328.

Show us a good schematic of your circuit.
Show us a good image of your wiring.

#5

larryd:
A Nano uses the same controller chip as a pro mini, A6 and A7 cannot be used as outputs.
Atmega328.

Show us a good schematic of your circuit.
Show us a good image of your wiring.

Thanks for the help - I got it working fine on pin D4. “Analog only” on A6/A7 I took as not pwm, int, etc, but still working for basic in/out. Didn’t see mention in any pinouts of it being analog IN ONLY.

Not sure why I had issues getting D13 going. I don’t need it, so I will leave on D5 since PWM will probably work better for me anyway.

#6