This circuit generates the busy tone of ordinary telephones. The transistors can be the BC548 and the components of the T filter and the multivibrator can be changed to obtain the exact tone.
This circuit, which in our times would be called a shield, can also be used with other loads. The...
This converter converts signals from the 50 MHz band to the AM band, making it possible to receive...
Other operational amplifiers series, such as the MC34072, MC34074, MC35071, MC35072, MC35074 d...