This analog meter circuit was found in the September 1989 issue of Radio Electronics magazine. The source must be dual, and the table gives the resistors for the various scales.
This circuit was found in old publication from 1958. The circuit uses germanium transistor, common in...
This circuit was obtained in a Popular Electronics of the 90s. It against a kitchen hood based on...
This 1968 Mullard circuit detects fire by smoke using LDR-type sensors. The circuit makes use of...