This RIAA equalizer preamp was found in a 1990s schematic. The transistors are an old version of the BC549 that can be used as a replacement. Signal input and output cable must be shielded.
This variable voltage reference uses a Norton operational amplifier. The voltage is adjusted at...
This low power, low voltage circuit was found in old General Electric documentation. Transistors may...
This flip-flop is triggered by touch and uses as a base a CMOS integrated circuit of type 4093....