This 1968 Mullard circuit detects fire by smoke using LDR-type sensors. The circuit makes use of transistors of the time that admit equivalents.
We have in the figure a traditional amplifier configuration with operational amplifier. The source...
This circuit was found in a 1977 Radio Shack documentation. The circuit is TTL, which must be...
This circuit is suitable for modulating small FM transmitters for eavesdropping or espionage. The...