This circuit uses a 7-segment display to indicate the logic level of a test circuit. The power supply is made with 5 V that can come from the analyzed circuit itself.
Crystals from 100 kHz to 1 MHz can be used in this 1957 Raytheon circuit. 4 can have values...
This preamp is from a documentation from the 60s. Of course, transistors are rare today, but the...
The L1 coil consists of 20 to 100 turns of fine wire in a cardboard box where plant specimens are...