Found in an Elektor from the 90s, this circuit converts signals from the 280 kHz band to 516 kHz, making it possible to tune them in common AM radios. The components used are from that time.
In this amplifier, the supply voltage is 35 V and the input resistance is 2k2. Equivalent...
This high speed laser diode driver was found in a 1980s documentation. Power FETs can be replaced...
This instrumentation amplifier with differential inputs was found in documentation from the 90s....