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.
This PLL circuit includes a small amplification stage. We found it in the December 1989 Radio...
Found in English documentation from the 1980s, this 3 transistors siren directly drives a small...
We found this circuit in a 1995 publication. It makes use of infrared LEDs of the type existing at...