- Grid leak
Grid leak is the small current through the grid of a thermionic valve into the circuit which feeds the grid. It is an inherent operating characteristic of
triodes and other vacuum tubes.This current is caused by the small negative EMF which is present in all vacuum valves as a result of a space chargewithin the envelope of the tube. The space charge is part of the thermionic effect, which is the fundamental phenomenon behind all vacuum tubes.
The grid leak detector was in common use in the 1920s in domestic
radioreceivers. The grid leak detector stage is a non-linear amplifier, which performs two, or more often three functions.
* Detection: The nonlinearity of the stage produces an
audio frequencydetected component in the anode load. In this circuit the grid acts like the anode of a diode. Detection takes place in the grid circuit.
* AF amplification: The stage is an AF amplifier as well as a detector, thus it gives much better sensitivity than a diode detector.
* Reaction: in most cases feedback was added to give reaction (aka regeneration) to boost sensitivity and selectivity further.
Wikimedia Foundation. 2010.
Look at other dictionaries:
grid leak — noun : a resistor used in parallel with a capacitor in the grid circuit of a vacuum tube to limit grid bias by drawing off excess electrons that accumulate on the tube grid * * * Electronics. a high resistance device that permits excessive… … Useful english dictionary
grid leak — /ˈgrɪd lik/ (say grid leek) noun a high resistance device which permits excessive charges on the grid of an electronic valve to leak off or escape … Australian English dictionary
grid leak — Electronics. a high resistance device that permits excessive charges on the grid to leak off or escape. [1915 20] * * * … Universalium
Grid-leak detector — A grid leak detector is a combination diode rectifier and audio amplifier used as a detector in vacuum tube A.M. radio receivers. In the circuit, the grid of the detector usually a low mu or medium mu triode is connected to the secondary of the… … Wikipedia
grid-leak rectification — tinklelinis detektavimas statusas T sritis fizika atitikmenys: angl. grid detection; grid leak rectification vok. Audiongleichrichtung, f; Gittergleichrichtung, f rus. сеточное детектирование, n pranc. détection par courant de grille, f;… … Fizikos terminų žodynas
Grid bias — is a DC voltage applied to electron tubes (or valves in British English) with three electrodes or more, such as triodes. The control grid (usually the first grid) of these devices is used to control the electron flow from the heated cathode to… … Wikipedia
Leak (disambiguation) — A leak is a a hole through which substances can escape or enter. It can also refer to:*Gas leak *Fuel leak *Grid leak, an operating characteristic of vacuum tubes *Internet leak, political leak, news leak, an unwanted transmission of information… … Wikipedia
grid detection — tinklelinis detektavimas statusas T sritis fizika atitikmenys: angl. grid detection; grid leak rectification vok. Audiongleichrichtung, f; Gittergleichrichtung, f rus. сеточное детектирование, n pranc. détection par courant de grille, f;… … Fizikos terminų žodynas
National Grid (Great Britain) — For the UK Ordnance Survey National Grid for mapping co ordinates in Great Britain, see Ordnance Survey National Grid. 400 kV power line in Cheshire The National Grid is the high voltage electric power transmission network in … Wikipedia
Tracer-gas leak testing method — As part of the recommended leak testing methods for nondestructive testing several tracer gas leak testing ones exist among which the methods of choice are: * Helium mass spectrometer or helium leak detection, providing the highest sensitivity *… … Wikipedia