This circuit is from March 1978 Radio Electronics. The 4-digit circuit uses a period module and is battery powered. The main integrated circuits are CMOS and TLL.
This circuit is intended to apply the music signal from a stereo to a telephone line for the...
This tachometer from a 1994 publication has a bargraph scale with the well-known LM3914 integrated...
This traditional triplier configuration with the 555 can be found in other articles on the...