This sensitive 5-band circuit was found in a September 1995 issue of Electronics Now magazine. The headphones, for greater sensitivity, should be high impedance.
Figure 1 shows a circuit than can be used as time stage in timers, and other applications....
August 2017 - The new N-channel MOSFETs from Vishay's TrenchFET Gen IV family can now be purchased from...
This circuit was obtained from an old Signalite documentation. Neon lamps are special types of the...