Found in a PE Hobbyst Handbook of 1991, this circuit was originally proposed to time photographic baths in developing rooms but can be used for other purposes. The circuit beeps at 30-second intervals.
This 3-decade operating range VCO was found in a 90s Popular Electronics. The circuit uses...
This circuit causes the powered lamp to fluctuate in brightness by 20% intensity. It can be used...
This circuit was found in a Motorola Manual of 1965. The circuit has neon lamps as trigger...