Found in a 1968 Motorola publication, this circuit generates a high-powered audio tone when triggered. Equivalent transistors can be used.
This simple low power stage with output transformer was found in an American documentation. The transistor...
This circuit was found in a British documentation from 1969. It can be implemented with modern...
The integrated circuit of this 80's project is not common today. This is the HA2530 which must be...