This circuit was found in a 90s Wels' Think Tank. The frequency depends on C2 and R3. The handset or speaker must be at least 80-ohm. Observe the low supply voltage.
This circuit was obtained from a Linear Technology manual from the 1990s. The sensor is of the...
This circuit is from a PE Hobbyst Handbook from 1991. The integrated circuit is a common 555 and...
This traditional circuit with a neon lamp is a flip-flop that draws which of the two lamps will...