Here’s a way of transmitting audio that makes it virtually impossible for someone else to listen in. Instead of sending radio waves bouncing all over creation, this uses the focused light of a laser ...

The intercom circuit described here uses two transistors, an audio transformer, and a few passive components in addition to condenser microphone and low-wattage speaker (refer Fig. 1). The complete ...

Remember Kenneth Lundgren’s unidentified audio transformer, discussed earlier and pictured here? There was no identification marking, so Kenneth invited thoughts from our readers about the type of ...

Pilot model 302 audio transformer. Marked: "Pilot No. 302 / Audio Freq. Transformer / Redi-Blox / Manufactured by / Pilot Electric Mfg. Co., Inc. / Brooklyn, New York, U.S.A." An audio output ...

Audio passed from lips to ears over short distances before the advent of radio. Broadcast changed that by using electronics to transport audio over great distances. As you know it starts with a ...

It was a cold January Saturday night in Chicago and we had big plans. Buddy Guy’s Legends bar was packed. We setup directly under one of the PA speakers less than 15′ from the stage. Time to celebrate ...

Using this low-cost project one can reproduce audio from TV without disturbing others. It does not use any wire connection between TV and Loud Speaker. In place of a pair of wires, it uses invisible ...