This circuit is intended to increase the width of a pulse. The circuit is TTL and can be used as a shield. We found it in an 80's Electronic Engineering.
The circuit presented is based on a mechanical tuning fork. The circuit is suggested by National...
This source, from a 1982 documentation, uses a triac to control the power and voltage applied to...
This circuit was found in a 1990 Electronics World magazine. The circuit can be mounted today by...