This circuit was obtained in an old Popular Electronics. It makes use of quite common components. The speed of the effect is set to R7. The circuit drives 20 LEDs.
This circuit is from a Radio Electronics magazine from August 1990. The indicator module is of a...
This flip-flop using two bipolar transistor was found in a publication of the year 1968. The...
This TTL siren is formed by two oscillators using each two Gates of a 7400. Frequency or the...