This circuit is from a 1969 EEE magazine. The transistors are from that time, but the circuit can be implemented with modern equivalents, such as 2N2646 for Q3.
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...