This high-impedance probe for oscilloscopes was found in a July 1958 Radio Electronics magazine. The circuit did not include a power supply.
We found this circuit in an English magazine from 1976. The magazine no longer exists, but just...
The figure shows a simple way to have emergency power for a 9 V circuit powered by a source. If...
Found in an Electronic Design from the 90's, this circuit supplies voltages according to the...