Introducing ELEC 3030

The first part of this lab I soldered wires to my speaker and inputted a 50 mV signal. After re-connecting the speaker the voltage dropped to 25 mV which did not produce a quality sound.

The next part of the lab I built the CE amp and placed it between the generator and speaker. After building the CE amp I built the CC amp which is shown in the picture to the right. After testing both amplifiers the CC amp had a louder sound output from the speaker.

After designing and testing the CE and CC amplifiers I built the two stage CE-CC amplifier circuit shown to the left. This amp produced a better sound output than the CC or CE amp by its self. To record the following amplitudes and gain I replaced the speaker with a 10 ohm resistor. The output amplitude was 860 mV and the input amplitude was 56mV which gave me a gain of 15.34 V/V. Next I calculated the power dissipation which came out to be around .9 watts.

Moving on to the next portion of the lab we had to build a basic class B push-pull amplifier which is shown to the right. The basic class B push-pull amp has a efficiency advantage but the drawback is it takes 0.7 V to turn on the transistor. The power dissipated was found to be 35.3 mW. When I set the input level to be 2V the top of the waveform had the shape of an ohm symbol.

The last section of part 1, I had to breadboard the AB push-pull amp by adding two diodes to the class B push-pull amp. The power dissipated found in this amp was slightly higher than the class B push-pull amp at 40.8 mW. After replacing the 10 ohm with the speaker the sound was dull and not loud. The calculated output amplitude was 86mV and the input amplitude was 20.8 mV. The gain for the Ab push-pull amp came out to be 4.13 V/V.

The LM386 audio amplifier was the beginning of part 2 of this lab. The calculated gain was 20 V/V. When playing with this amplifier I managed to make the gain 50 V/V and the sound output was very strong when I added a 1.2k ohm resistor and 10uF capacitor in series. The power dissipated came out to be 45 mW.

In the last part of the lab we had to build an op amp amplifier which should produce a high gain. The figure on the left is  the op-amp audio amplifier with a class AB second stage. The power dissipated in this circuit was 40.5 mW with a gain of 4.45 V/V.