Found in American documentation from the 1980s, this circuit uses common components. The operating frequency range depends on the plug-in coils.
This is one of many zero crossing detector that can be found in this section. It was found in...
This circuit with zener diodes was found in documentation from the 90s. The zener diodes determine the...
Found in a PE Hobbyst Handbook of 1991, this circuit was originally proposed to time photographic...