Glow stabilizer
A glow stabilizer or stabilizer tube (also known as a smoothing tube) is a gas-filled tube similar to a glow lamp , which was previously used in devices equipped with tubes for voltage stabilization and for generating reference voltages .
For voltage stabilization with glow stabilizers, their non-linear current-voltage characteristic is used, which occurs due to the impact ionization and is characterized by the fact that the operating voltage after the ignition of the gas discharge is largely independent of the current flowing. Neon was used as the filling gas .
Glow stabilizers are switched as cross regulators ( shunt regulators ) and always require a series resistor. As shown in the typical circuit shown on the right, so much current must always flow through the tube that it is within its specified stabilization range (flat part of the current-voltage characteristic ). The example circuit in the picture stabilizes the unstabilized DC voltage supplied on the left to a stabilized nominal output voltage of 85 V. If the stabilized voltage is to supply current, the series resistor may have to be correspondingly smaller. The differential current between the input current and the minimum current of the tube (for example 3 mA for the SR44 and 0.5 mA for the SStR85 / 5) can be taken. It should not be more than three times the tube current. The maximum current through the tube (in the example 5 mA) may only be exceeded for a short time. A run-in time (stabilization of the characteristic values after switching on) of 3 minutes is specified in the data sheet for various types.
Glow stabilizers were manufactured for one or more output voltages. They had bases similar to those of electron tubes , but also bayonet or screw bases . Due to the adsorption of the filling gas, they are wearing parts and therefore had to be easy to replace.
In order to reduce or avoid the difference between ignition and operating voltage (it would require a large voltage drop at the series resistor), the following measures were applied to glow stabilizers:
- Ignition electrodes: The ignition electrode, which is continuously operated at a higher voltage via a series resistor, also allows such stabilizer tubes to be connected in parallel and prevents them from going out in the event of deviating burning voltages
- Radioactive gas filling: For safe ignition and lowering the ignition voltage, radioactive gas (e.g. Krypton 85) was added to the gas filling.
The semiconductor analogue of the stabilizer tube is the zener diode .
Web links / individual references
- ↑ [1] SStR85 / 5, comparative type of the SR44: 0.5 mA minimum current (catalog gas discharge tubes of the VEB factory for television electronics 1968, 209 pages, page 29), accessed on December 17, 2018
- ↑ Friedrich Benz: Measurement technology for radio engineers , Springer-Verlag 2013, 516 pages, page 33
- ↑ http://www.tubecollection.de/ura/stabilisatoren_fotos_gr-typen.htm Photos of different glow stabilizers
- ↑ http://www.radiomuseum.org/forumdata/users/5100/AN_GR150_FS0341.pdf Application of glow stabilizers
- ↑ http://hiq.linde-gas.com/en/images/Rare%20Gas%20Krypton-85_tcm899-90088.pdf Applications of 85 Kr, company publication Linde AG
- ↑ https://www.sokoll-technologies.de/Museum/Auto/Typen/5651.html Röhren-Datenammlung Patric Sokoll, accessed on December 17, 2018