This shield circuit was obtained from Radio Electronics magazine, July 1990. The triac is load and power grid dependent.
This circuit was found in a 1977 Radio Handbook. Equivalent transistors can be used. The formula...
This circuit was found in a Popular Electronics from the 90's. The circuit has gained 10 to 20 dB...
The purpose of this circuit is to increase the sensitivity of a common multimeter in its voltage...