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Later thermionic vacuum tubes, mostly miniature style, some with top cap connections for higher voltages. A vacuum tube, electron tube, [1] [2] [3] valve (British usage), or tube (North America) [4] is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied.
Eveready 761 "C" battery with 4.5-volt, 3-volt, 1.5-volt tap screw terminals. The "C" battery is used to provide bias to the control grid. Until the early 1930s this was common practice in valve (tube) radio sets but was largely superseded by grid leak resistors or voltage divider biasing. Because the tube grids draw no current, the "C" battery ...
Valve receiver made by Marconi Co. has two Fleming valves, in case one burns out The valve consists of an evacuated glass bulb containing two electrodes : a cathode in the form of a " filament ", a loop of carbon or fine tungsten wire, similar to that used in the light bulbs of the time, and an anode ( plate ) consisting of a sheet metal plate.
A thermal expansion valve or thermostatic expansion valve (often abbreviated as TEV, TXV, or TX valve) is a component in vapor-compression refrigeration and air conditioning systems that controls the amount of refrigerant released into the evaporator and is intended to regulate the superheat of the refrigerant that flows out of the evaporator ...
A solenoid valve is an electromechanically operated valve. Solenoid valves differ in the characteristics of the electric current they use, the strength of the magnetic field they generate, the mechanism they use to regulate the fluid , and the type and characteristics of fluid they control.
The grid is constructed of a helix or screen of thin wires surrounding the cathode. The anode is a cylinder or rectangular box of sheet metal surrounding the grid. It is blackened to radiate heat and is often equipped with heat-radiating fins. The electrons travel in a radial direction, from cathode through the grid to the anode.
Image credits: lizzobeeating “Sometimes, it can have the effect of actually making a person look older — because the fat in our cheeks is what gives us a more youthful look.”
The most efficient valve-based RF amplifiers operate class C. If used with no tuned circuit in the output, this would distort the input signal, producing harmonics. However, class C amplifiers normally use a high Q output network which removes the harmonics, leaving an undistorted sine wave identical to the input waveform.