The purpose of this lab is design and test a two-stage BJT amplifier.

For this lab keep records in your notebook as you have been. I will check your notebooks later. Do not hand in the notebook but use it to write a formal lab report a week later. The report should be typed or computer printed. Include an introduction, design, design choices and decisions, hand analysis, spice analysis, tests, results, and conclusion.

Design a capacitive-coupled two stage amplifier. Both stages will be common-emitter amplifier. Use + 15 and -15 V power supplys. The input will be your digital signal generator with an source resistance of 10 k (added in series). v_in is at the junction of the 10 k and the signal generator. Measure the output with a load of 20 k. The output voltage swing must be linear to at least 6 V p-p, and the gain (v_out/v_in) must between 50 and 60 V/V. Use 2N3904's (npn) and/or 2N3906's (pnp) (both are rated at 100 mA and 40 V reverse breakdown).

Before coming to lab analyze your design, finding the bias voltage at each node, the gain, R_in and R_out. This will save lots of time.

Build and test the amplifier. Measure the dc voltages that determine the bias conditions. These should agree with your calculated values.

Measure the gain at 10kHz.

Measure R_in and R_out as you did in lab #8.

Extra credit. Use a current mirror for the bias (Figure 4.42 in Sedra and Smith).