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 small transmitter for telegraphy (CW) or remote control operates at the frequency determined by the...
The circuit, from Motorola's 1993 Linear Interface ICs, uses an unusual operating system today....
This interesting source, obtained in a 2001 catalog, can vary the output voltage between -16 and...