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 |

Adjustable Square Wave Generator (CB13638E)
We found this circuit in a publication for radio amateurs in 1974. The bipolar transistors can be...
Crystal oscillator (CB9637E)
Found in a 1980s American documentation, this circuit has a current consumption of only 1 mA. The...
0 to 30 V power supply with 1A (CB21853E)
This adjustable power supply was found in Ferranti's transistor manual from 1974. Power...