This circuit for the 40 MHz band was published in Radio Electronics magazine in December 1957. Its purpose was to monitor the signals of the Russian satellite launched at the time.
By pressing and releasing PB1, only one LED is lit, drawing a number from 1 to 6, as in a die. The...
We found this circuit in the National Semiconductor Linear Applications Handbook of 1994. The...
The transformer inf this circuit is a 6 or 9 V unit and diodes 1N4002. The filter capacitor is 2...