Found in 1980s Electronic Engineering, this circuit uses common phototransistors as sensors. The circuit is CMOS using an integrated 4011.
The 4518 can be cascaded to count to values higher than 10. The output EN of this device can be...
This oscillator uses a ceramic resonator to determine the frequency. This kind of element is found...
This small transmitter appeared in the March 1989 issue of Radio Electronics magazine. The...