This circuit is from the 80's, using an integrated of the time. The circuit serves as a reference, as this type of dialing is no longer used today.
ROHM Semiconductor is featured in a new line of IR LEDs, Proximity Optical Sensors and Ambient...
Found in a documentation by Hugo Gernsback from 1960, this receiver uses germanium transistors of the time...
In the figure we have the way to connect several 555 to obtain sequential operation. The component...