This circuit was obtained from HAM Radio magazine in an 80's issue. The FETs are types of the time and the frequency is determined by the crystal. The circuit operates at voltages from 3 to 9 V.
This circuit that imitates the sound of the cowboys' calls with their “louder” was found in a...
We found this circuit loader in a French magazine Electronique Radio Plans from July 1993. The...
We have in the figure a traditional amplifier configuration with operational amplifier. The source...