We found this circuit in an old publication. The components used are rare today. Accuracy depends on the resistors in the input selection network. The circuit operates from 10 to 500 kHz.
The trip circuit for this alarm is given in CB16765E. The circuit uses common components and acts...
This circuit is from an old American publication from 1970, but it can be assembled with a BF494...
This circuit found in 1969 Popular Electronics is used to power a gas laser. The circuit produces...