The power transistor of this circuit can also be the TIP42 mounted on a good heat sink. The circuit is from old European documentation and the integrated circuit used is not very common today.
This circuit uses a crystal phone and can be built with more modern transistors like the BC548. The...
The resistors in this circuit marked with * must be within 1% tolerance. The circuit is from the...
The existence of field effect transistors at the input of the integrated circuit (operational...