This circuit was found in documentation from the 1970s. However, it can be implemented with modern transistors such as 2N2222 for Q1 and BF494 for Q2. The crystal depends on the desired frequency.
The purpose of this circuit is to allow common analog multimeters to measure low resistances, on...
Found in American documentation from the 1980s, this circuit uses an ADC from that time, which is...
We found this configuration in a 1974 publication. Transistors can be replaced with equivalents such as...