This simple TTL siren was found in a 1980s Electronics Today International. The power supply is 5 V and the integrated circuit can be the 7400.
This circuit was obtained from Radio Electronics from the 90s. The infrared sensor is of an...
This circuit is from the 1993 Motorola Linear Interface ICs. The circuit must use symmetrical power...
This circuit was found in the magazine of radio amateurs 73 in a 90's edition. The components are...