This audio oscillator directly feeds a piezoelectric transducer or crystal capsule producing a continuous tone which depends on the values of the capacitors used. These capacitors can have values between 10 nF and 1 uF.
The circuit can be powered by batteries, battery or power supply and its consumption is very low. We can use it in small alarms, warning or call systems or even toys. The circuit will also work with the 4011 CMOS. In Figure 1, we have the complete diagram of the oscillator.
The assembly can be made on a breadboard or even on a small printed circuit board with the pattern shown in Figure 2.
The circuit can also be used with a good signal injector, because the rectangular signals generated are rich in harmonics.
Material list
CI1 -4011 - CMOS integrated circuit
BZ - Ceramic transducer
C1 and C2-10 nF at 1 uF- polyester or ceramic capacitors
R1 and R2- 100 k hms x 1/8 W- resistor - brown, black, yellow
Miscellaneous: printed circuit board, wires, solder, etc.
