Found in a 90s 73 magazine for radio amateurs, this circuit makes use of common operational amplifiers.
This circuit is from a 1997 English magazine, but it is very current due to the components it...
This system of sequential LEDs has its speed adjusted in a 1 M ohm potentiometer and this speed...
This is the commercial circuit for the TRF-44 amplifier sold in Japan in the 1960s. The circuit...