Astable 555 (CB21101E)

This 50% duty cycle configuration was found in a Popular Electronics from the 1990s. The operating frequency is given by C1.

SCR Passage Alarm (CB13378E)
We found this circuit in an old documentation from the 70s. The sensor is an LDR that must be...
Low noise preamplifier (CB12987E)
This low noise audio amplifier stage uses only one transistor and has a high enough gain to...
Intermittent Tone Generator 556 (CB19099E)
In fact, the 556 consists of a double 555, which can be replaced by these integrated ones. The...