This circuit from a Popular Electronics from the 90s uses a common optocoupler and a general-purpose transistor to control a sensitive relay that can be from 6 to 12 V.
This circuit uses a unijunction transistor in a different configuration to generate rectangular pulses at...
What this circuit does is generate a signal in a ladder pattern, containing steps in which the...
This circuit was suggested by General Electric / RCA in a 1980s documentation. The components are of...