Search the collections
Microphone - New Wilson Electrical Manufacturing Co, Magnetic Microphone Bar, 1927 Reg. No: HT 26207
- Carbon microphone used in association with a headphone (not present) to form a valveless amplifier. It was probably manufactured by New Wilson Electrical Manufacturing Co. Ltd in 1927.
The bar replaces the diaphragm of a headphone earpiece so the bar now vibrates instead of the diaphragm. The earpiece is connected to the output of the radio (usually a crystal set). The movement of the microphone bar changes the resistance between the microphone terminals (ie the resistance between the screw and the carbon). A pair of headphones (for listening) is connected via the microphone terminals to a battery.
A control knob allows adjustment of the sensitivity of the microphone part.
- A rectangular metal shaped object with a black disc attached to one side with a screw. There is one terminal on the body and another on the black disc.
Internally there is a carbon block mounted between two nickel plated ends joined by a blunt ended oval shaped piece of magnetic material. The screw, on the opposite side, can be adjusted to optimise the pressure between the carbon and the contact for maximum sensitivity.
|Dimensions:||55 mm (Height), 25 mm (Width)|
|Themes this item is part of:||Information & Communication Collection|
|Inscriptions:||On metal body: " MAGNETIC / MICROPHONE / BAR ", " PATENT No / 248581-25 "|
|Manufacturer (Probable):||New Wilson Electrical Manufacturing Co. Ltd., London, England, 1927
Radiomuseum http://www.radiomuseum.org/r/newwilson_microphone_bar_amplifier.html accessed 22 Nov 2011
|References:||Radiomuseum http://www.radiomuseum.org/r/newwilson_microphone_bar_amplifier.html accessed 22 Nov 2011|