The capacitor used in this circuit can have values between 5 and 30 uF. The circuit is of old documentation for radio amateurs. Observe the special source used in the supply.
I found this circuit in a 1979 documentation. The phone must be at least 1k magnetic or crystal...
This simple circuit is designed to charger AA or AAA Nicad batteries. Current can be changed...
This circuit converts voltages from 5 to 12 V at voltages of 100 to 400 V. The transformer has a...