Need desperate help on BJTs

Thread Starter


Joined Sep 14, 2006
I'm having trouble in lab of my course and this post is my last hope. I just spent three hours trying to figure out how to measure Base Current, Collector-Emitter Voltage, and Collector Current with a 2N3904 transistor on a breadboard. The three hours were wasted as I came out with no results.

Here's the lab for reference (LAB 6 page 12 and 13 of the following link): Lab Manual_1.doc

Worst of all, I have will have a quiz on BJTs. Could someone draw wiring diagrams on a beardboard with a 2N3904 transistor that measures the following? I'm speaking of a common-emitter configuration.

Base Current
Collector-Emitter Voltage
Collector Current
Collector Voltage (is this the same as Collector-Emitter Voltage?)
Small Signal Beta

If you were measuring Collector Current versus Collector-Emitter voltage for a fixed Base Current, does that mean you supply a voltage to the Base lead of the transistor (therefore giving it fixed current), then apply several different voltages to the Collector-Emitter leads and record down both the Collector Current and Collector-Emitter Voltage?

I would also like to know how you would go about measuring the voltage/current gain of a simple transistor.

Definitely appreciate the help and would kill for it.:D