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Tune Indicator - AWA, Spark Transmitter, 1914-1920 Reg. No: ST 021422
- Tune (tuning) indicator: a lamp is connected to one end of a loop of wire and a adjustable tap. The loop is placed in series with the earth lead of the jigger secondary coil, and the tap is adjusted to give a reasonable brightness at maximum antenna current. Other positions might lead to bulb burn-out or the lamp being too dim to observe the light.
The lamp indicates by its brightness the current in the aerial circuit, which is adjusted for a maximum by varying the tuning inductor (jigger or spiral inductor).
Tune indicator ST 021416 achieves the same result as ST 21422 but in a different way.
- Varnished wooden board with an approximately 270 degree arc of wire connected to two terminals. A wiper arm, fitted with a knob, is connected one side of a lamp socket; the other side is connected to one end of the loop. The globe is missing.
- Acquisition Information:
- Donation from Amalgamated Wireless (Australasia) Ltd., 1940
|Dimensions:||55 mm (Height), 150 mm (Width), 153 mm (Length)|
|Tagged with:||radios, electrical components, resistors|
|Themes this item is part of:||Information & Communication Collection, Radio from sparks to valves, 1914 - 1920|
|Inscriptions:||Base: AMALAGAMATED WIRELESS / (A-SIA) LTD / No 87-4837 SYDNEY. N.S.W. / AUSTRALIAN MANUFACTURE|
|Manufacturer:||Amalgamated Wireless (Australasia) Ltd., Sydney, New South Wales, Australia, 1914-1920|