Telephones & Microphones
How to Make Them and Use Them

edited by Percival Marshall
reprinted by Lindsay Publications

These days people rave about DVD players, surround sound, and all the high-tech gear that comes out of Asia and have no clue as to how it works. But a hundred years ago in England, experimenters wanted in the worst way to have a telephone. It was a magical device. And about the only way they could have one, was to build one. Fortunately that was something they could certainly do.

Here you get details on building simple telephones. And that in itself is an interesting little experiment in electricity, metal working, and woodworking.

But the components of a telephone are essential to early radio as well. The receiving end is a small electromagnetic speaker. Early experimenters strapped two of them to their ears with an flexible band and called them head-telephones, or later, just headphones.

And the early amateur radio operators wanted to transmit their voice in addition to morse code. So what did they use for a microphone? Of course. The carbon microphone salvaged from an old telephone. If you look at photos of amateur stations from the 1920's you'll often see a candle-stick phone (you know, the kind Eliot Ness might have used...). And they used it to transmit AM. The old-timers today still talk about getting out on 75 meter "phone".

So what you get here are the details of building carbon mikes, and magnetic earphones. You get details on wiring them up into working telephone system with batteries, bells, ringing key, induction coil and more.

If you're looking for a science project or want to build your own radio equipment, or even build a replica of an early telephone, you oughta have a copy of this. It's an interesting little book worth having in your electricity reference library. The price is right. Get one! 5-1/2 x 8-1/2 softcover 80 pages

No. 23047 ... $7.95