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This circuit was found in a 80’s Popular Electronics. It issues a warning signal with the signal of the old type printer with parallel port.
This signal injector circuit, an astable multivibrator, was found in a 1971 magazine. The circuit can...
This circuit that can only be used with simple resistive and inductive loads (never electronic) was...
This circuit activates a relay at dawn. The relay can be used to sound an alarm, turn on a radio...