Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 194

Circuit 171: Buffer amplifier for condenser microphone
Setup information
Install the transistor, the two resistors and the two ceramic capacitors as shown in Fig. 2.171. The three
jumper wires come next. Check the placement on the board again and only then connect the battery.
Experiment
This circuit is a simple buffer amplifier. The input has high impedance, the output has low impedance. A
signal is not amplified and thus provides the ideal conditions to operate a condenser microphone or an
electret microphone on a normal amplifier port.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.171.
196
Components required:
1 x J111 FET transistor,
1 x 2.2 kΩ resistor,
1 x 1 MΩ resistor,
1 x 1 μF electrolytic
capacitor, 1 x 10 μF
electrolytic capacitor,
1 x breadboard, 1 x 9V
battery with clip con-
nector
Fig. 2.171: Buffer amplifier for
condenser microphone