This simple logic level tester was found in Radio Electronics from the 90s. The inverters are of the 4009 type and the power comes from the circuit being analyzed.
This power supply is protected from shorts in the load. The BD135 must be mounted on a heatsink...
This amplifier for audio transmission lines was found in a 1961 American publication. The critical...
The maximum frequency of the oscillator shown in figure 10 is on the order of 5 MHz, depending on the...