This high-impedance probe for oscilloscopes was found in a July 1958 Radio Electronics magazine. The circuit did not include a power supply.
April 2017 - Texas Instruments' new high-precision TMP468 sensor can now be obtained from Mouser...
This circuit was found in Motorola documentation from 1968. SCRs can be modern equivalents and the...
We found this circuit in April 1979 Radio Electronics magazine. The circuit is based on the 555...