Rectangular and triangular generator (CB21333E)

This circuit, based on a 555, was found in a Popular Electronics from the 90s. The circuit has the frequency determined by R1, R2 and C1.

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Timer for enlargers (CB8351E)
Suggested for the control of photographic enlargers, this 1967 General Electric circuit uses still...
Car Alarm (CB4412E)
We found this alarm in a 1992 documentation. The circuit has several timings and the relay can...
Test for LEDs and Microlamps (CB17277E)
This is a circuit for testing small lamps and LEDs. The lamps that can be tested are the ones...