Telegraph relays amplified electrical signals in a telegraph line. Telegraph messages traveled as a series of electrical pulses through a wire from a transmitter to a receiver. Short pulses made a dot, slightly longer pulses a dash. The pulses faded in strength as they traveled through the wire, to the point where the incoming signal was too weak to directly operate a receiving sounder or register. A relay detected a weak signal and used a battery to strengthen the signal so that the receiver would operate.
This relay includes a marble base and was made by Charles T. Chester of New York City. The electromagnet coils are fixed but the steel core can be moved to adjust the strength of the magnetic field.
This Akai reel-to-reel tape recorder was imported from Japan in the late 1960s. The professional-grade recorder used transistors rather than older style vacuum tubes. That reduced power consumption and made the electronics much lighter. However, the unit features a wooden case and cover that makes it heavier than most recorders in the collection.
Japanese industrialists viewed the task of rebuilding after World War Two as an opportunity to modernize their production facilities and product lines. The transistor was one new technology in which they invested heavily.
A 2-piece cylindrical plastic housing with slide switch on top, battery door on back. 2 phillips screws hold unit together. A metal shaft emerges from the front of the unit. A separate plastic whisk slides onto the shaft to provide mixing action. Operates with 2 AA batteries. Includes original package. Purchased at a Cockeysville, MD antique shop in 1999.
This unit (with its original fluorescent tube attached) was intended to replace one lamp in a two-lamp fluorescent fixture. By modifying the impedance of the circuit, a 50% reduction in light output could be obtained with an almost equal power saving. Sylvania marketed this 50% reduction unit and a 33% unit as stop-gap measures in response to the electricity price spikes during Energy Crisis. Characteristics: Medium bi-pin base with fiber insulator. Coil-core transformer to provide current for electrode warming, a 2 microfarad capacitor, and a bi-metal switch are housed in a two-piece, clam-shell style plastic housing. Lamp given to donor by co-inventor William Roche in 1996. (Interview on file). See also, US patent 4,163,176 to Cohen, Paget, Roche, Sadoski, and Bessone; and Impedance Modified Fluorescent Lamp by Cohen and Sadoski in Journal of the Illuminating Engineering Society, April 1979, page 179.