Bike speedometer (CB20497E)

This circuit can be powered by a solar cell. The circuit is from a 1991 documentation having a phototransistor as sensor.

Auto alarm (CB16766E)
The trip circuit for this alarm is given in CB16765E. The circuit uses common components and acts...
Regenerative VHF Receiver (CB13502E)
This circuit is from an old American publication from 1970, but it can be assembled with a BF494...
Gas LASER Supply (CB7227E)
This circuit found in 1969 Popular Electronics is used to power a gas laser. The circuit produces...