Phase Shift Oscillator (CB20565E)

This low-frequency oscillator was found in a 1963 documentation. Capacitors determine frequency. The transistor used is germanium.

Level Indicator 741 (CB1279E)
This didactic circuit from a 1977 Radio Shack documentation shows how to use the 741 as a...
HV9805 High Voltage LED Driver (COM124E)
September 2015 – It can be found at Mouser Electronics the new drivers of high voltage LEDs HV9805 from...
Solar Battery Test (CB1355E )
This circuit is of great use today, when solar energy is becoming increasingly important. The...