Found in a Hands-On Electronics from the 90s, this circuit produces the dial tones of an old telephone. The integrated circuit used is uncommon today.
This circuit is from an American documentation from the 90's. The SCR can be of any type and the...
This transmitter has the frequency that depends on the crystal. We find it in a 1980s...
Found in old documentation, this circuit is intended for low level amplitude modulation with low...