This simple tester was found in a Popular Electronics from the 90s. The circuit is powered by two 9 V batteries since it requires a symmetrical source.
This circuit keeps the neon lamp on for a moment when it receives a pulse. The turn on time...
This circuit was obtained from an English magazine from 1976. What this circuit does is start from...
We found this amplifier in a publication of 1990, but it can be mounted today with some exchanged...