Found in Motorola documentation from the 90's, this circuit has a high input impedance. The power supply must be symmetrical. The circuit can be implemented with modern operational amplifiers.
This simple 4-bit digital-to-analog converter was found in a 1974 publication. The transistors can be the...
I found this circuit in an American magazine Hands On Electronics from September 1987. The...
Of course, the current is extremely small, but a voltage of 300 V can be obtained from 9 V of a...