This circuit was found in a Popular Electronics from the 90's. The CMOS integrated circuit used is not very common nowadays. The range depends on the infrared LEDs. R7 can be changed.
This circuit is suitable for applications in medical, research and industrial equipment. The...
This circuit, found in a publication of the year 1968, uses a transformer to drive two power...
This 100-second timer was found in a 2000 Poptronics. The magazine no longer exists, but the...