This is the receiver from the previous alarm system. The circuit is from Radio Electronics, April 1989, and has an LDR as the sensor. Optical devices should be used to improve performance.
This circuit generates low-frequency sinusoidal signals. The variable capacitor is dual and the...
This circuit was found in a 1980s documentation. It triggers a relay when liquid from a reservoir...
This circuit was found in the January 1995 Electronics Now magazine. Its configuration is valid for...