Hi all,
I am trying to use a transistor (2N222A) to control a relay, but having trouble. To reduce the number of variables I have removed the relay (and other stuff) from the circuit to see if I could just get a bare bones transistor circuit to work, but I'm still confused. Below is the simple test circuit.
I took a number of measurements of V3 across the resistor for different V1, V2, and R to see if I could figure out what was going on:
It looks like the voltage across the resistor V3 is basically V2, the base input voltage, minus a little drop across the transistor. So it's basically acting as though I just had only V2 across the resistor and no transistor or V1 at all. I was under the impression that the function of a transistor was to act as a closed switch when a voltage was applied at the base, which should bring V1 into play. Why is this apparently not the case?
I am trying to use a transistor (2N222A) to control a relay, but having trouble. To reduce the number of variables I have removed the relay (and other stuff) from the circuit to see if I could just get a bare bones transistor circuit to work, but I'm still confused. Below is the simple test circuit.
I took a number of measurements of V3 across the resistor for different V1, V2, and R to see if I could figure out what was going on:
It looks like the voltage across the resistor V3 is basically V2, the base input voltage, minus a little drop across the transistor. So it's basically acting as though I just had only V2 across the resistor and no transistor or V1 at all. I was under the impression that the function of a transistor was to act as a closed switch when a voltage was applied at the base, which should bring V1 into play. Why is this apparently not the case?