This shortwave preselector was found in the July 1994 issue of Radio Electronics magazine. The circuit is suitable for telescopic antennas, matching the impedance with the receiver used.
This digital electronic dice was found in a 1977 magazine, but it can be easily assembled today, as...
This circuit converts sinusoidal signals into squares and can be powered by voltages from 1.5 to 5...
When the sensor receives light, the relay closes its contacts and remains so even after the light...