Here’s what this schematic is saying:A batteryis used to supply 6 volts to the
circuit.
S1 is an SPST switchthat turns the power to the circuit on or off.An electret microphone(MIC) transforms sound waves into electrical
signals.
A resistor (R1) connects the microphone to the positive battery termi-
nal and supplies the 3 volts required to make the microphone function.
Note the dots above and below R1 that indicate connections.C1 is a capacitorconnected between R1
and R2.
R2 is a potentiometerwith one lead connected to C1, one lead con-
nected to the negative battery terminal, and the variable contact con-
nected to Pin 3 of R2.IC1 is an audio amplifier (op amp)connected at Pin 3 to R2.
Pins 2 and 4 of IC1 are connected to the negative battery terminal.Pin 6 of IC1is connected to the positive battery terminal.
Capacitor C2 is connected between Pins 1 and 8 of IC1. The positive side
of the capacitor is connected to Pin 1.Capacitor C3is connected between Pin 7 of IC1and the negative battery
terminal.
Capacitor C4is connected between Pin 5 of IC1 and the speaker (or
headphones).Capacitor C5 is connected between Pin 5 of IC1 and resistor R3.
Resistor R3 is connected between capacitor C5 and the negative battery
terminal.The speaker (in this case, headphones) is connected between capacitor
C4 and the negative battery terminal.Breadboarding ................................................................................................
A breadboardis a temporary place to build and test a circuit for an electron-
ics project. You don’t have to solder the circuit; just insert components and
the wires, connecting them into handy little holes.When you’re sure you have your circuit right, you can create permanent
boards by soldering or by ordering printed circuit boards. See Electronics For
Dummies,by Gordon McComb and Earl Boysen (Wiley), for some detailed
descriptions of these processes.Chapter 4: Running Down the Skills You Need 65