Noninverting Two-Power Supply Amplifier
Électronique / Electronic
NE5532

In this project, we make a microphone amplifier, using the operational amplifier as a non-inverting amplifier with two power sources. The earphone works as a microphone.

Start by sliding the switch to position OFF and completing the wiring for the circuit.

When you finish connecting the wires, set the switch to position ON to turn on the power, rotate the control fully clockwise, and lightly tap your microphone-the earphone. The tapping sound comes through the speaker. When you use the earphone as a microphone, as in this project, it's better to remove the end that you put in your ear. You can unscrew it by turning it counter-clockwise.

Turning the control adjusts the volume. As you can see in the schematic, the dual operational amplifier uses two power sources: 4.5V for the circuit and 9V for the IC. Note that the dual operational amplifier has two input terminals, the positive (+) and negative (-).

The noninverting input is applied to the positive (+) terminal. The gain in strength of the signal through this amplifier is about 100-determined with the formula R1/R2. Thus 100K/1Κ = a gain of 100.