Sinusoidal Oscillator 741 (CB8426E)

Found in a 90s Popular Electronics, this circuit uses a 741 to generate frequencies from 0.1 to 30 Hz. Observe the phototransistor feedback.

| Clique na imagem para ampliar |

Flashing mobile bar with 4017 (CB25434E)
This circuit was obtained from the February 1992 Radio Electronics magazine. In it, a bar of 4...
Two meter amplifier (CB8980E)
This circuit for the two-meter band of radio amateurs was found in 1980s documentation....
Dog Remote Control –Transmitter (CB25465E)
This programmable circuit emits a signal that can be sensed by the dog at a distance. The circuit is...