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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 conventional power supply uses integrated regulators for 1 A. Several regulators are used. The...
This circuit was found in an old publication from 1989 but can still be assembled today with BD135...
This circuit was found in a 1988 publication. The circuit is an alarm with interrupt sensors that...