This transmitter for the 3.5 and 7 MHz ham radio was found in a 1950s Japan publication. No information was given on the coils and the power supply.
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....