This circuit generates short pulses. The transistor can be a 2N2222 or BC548 and the frequency is given by the resistors and the capacitor that can be changed.
The integrated circuits in this application are not very common today. One consists of an A / D...
Found in the Encyclopedia of Electronic Circuits Volume 5 of 1995 this circuit has the gain...
The output power of this amplifier depends on the supply voltage that can be between 3 and 16 V....