This small source for low consumption projects was found in an old national documentation. The transistor is for general use and the transformer has 50 to 100 mA of secondary current.
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....