Frequency Base 555 (CB24503E)

This mains-synchronized circuit produces a simple 1 pulse per second. The circuit is from a Radio Electronics magazine from May 1977.

| Clique na imagem para ampliar |

Wien Bridge Oscillator (CB8089E)
This circuit generates sinusoidal signals between 300 and 3000 Hz. We find a 303 Circuits from the 90's....
Line Amplifier (CB19052E)
This amplifier for audio transmission lines was found in a 1961 American publication. The critical...
Intercom with telephone (CB7829E)
Old phones with dials can be used in a simple home intercom system, as this circuit from Popular...