This circuit is from a 1968 Electronic Design. The circuit uses transistors of the time that can be replaced with modern equivalents. More stages can be used to get higher tension.
This configuration from a 1976 technical documentation shows how to use a varicap in a direct...
This circuit was found in the October 1979 issue of Radio Electronics magazine. The circuit is...
When this alarm is off current drained is very low, only about 60 µA. The circuit can be powered...