In the early days of electronics, vacuum tubes (called valves in the English context) devices (such as radio) are powered by batteries. Each battery has different assignments depending on the vacuum tube element associated with it.
Initially, the only device is a diode with only a filament (cathode) and a plate (anode). Following the direction of electron flow, these electrodes are identified as "A" and "B", respectively and thus related batteries are referred to as "A" batteries and "B" batteries, respectively. Then, when a grid control element is added to create a triode tube, it is logically given the letter "C" and supplied from the "C" battery. The subsequent addition of further internal elements to improve triode performance does not require an extension to this battery series - these elements are biased resistively from existing batteries, connected to ground or to the cathode.
This nomenclature is used primarily in North America. Different battery names are used elsewhere in the English-speaking world.
Video Battery (vacuum tube)
Battery
A Battery is the battery used to provide power to the filament from a vacuum tube. Sometimes colloquially referred to as "wet battery". (Dry cells can be used for that purpose, but the ampere-hour capacity of the dry cells is too low at the time to be used practically in this service). The term is derived from the days of radio valves (tubes) when it is a common practice to use dry batteries for plate voltage (anode) and rechargeable "wet" lead/acid batteries for filament voltages. (Filaments in vacuum tubes consume more current than the anode, so the "A" battery will flow much faster than the "B" battery, therefore, using rechargeable "A" batteries in this role reduces the demand of the battery. Instead, the battery A non-rechargeable "B" needs to be replaced relatively often.)
Battery originally 2 volts, is a lead acid accumulator, but with the introduction of all radio dry batteries, 1.4 volts became more common. Other voltages can be found. For example, a 7.5 volt battery is sometimes used to power a 1.4 volt valve connected set (tube).
In the UK and some other countries, the "A" battery is known as "LT" (low voltage) battery if it is dry, and only "accumulator" if wet.
Maps Battery (vacuum tube)
B battery
Battery B is the battery used to provide the plate voltage of a vacuum tube. Sometimes colloquially referred to as "dry battery" (although there is no reason why a "wet" battery of an appropriate voltage can not be used for that purpose).
The filament is primarily a heat source and therefore A battery provides significant current and rapid discharge. Battery B has relatively small appeal and maintains its storage capacity much longer than battery A. Early B batteries used with bright emitter tubes are 120 volts, but these quickly become obsolete as they are replaced by samples that have a voltage typically 45 volts, 67Ã, ½ volts, or 90 volts because more efficient tubes become available. Some examples tapped every 22 ½ volt.
Even when the plate voltage rails are fed by the power supply rather than the battery, it is commonly referred to as the "B" line in the American scheme.
Since the plate voltage can be as high as 300V DC, some B batteries can be connected together in series to additively provide the required operating voltage. The higher battery B voltage available means that the battery should be handled more carefully than other types of batteries due to its ability to shock and/or burn the person who handles them.
In the UK and in some other countries, battery "B" is known as "HT" battery (high voltage).
Battery C
In electronics, the battery C may refer to a battery used to provide bias to the control network of a vacuum tube. Until the early 1930s this was a common practice in radio circuit valves (tubes) but was largely replaced by grid-leaked resistors or divider voltage dividers.
Grid biased batteries are still produced today, but not for radio use. They are popular in schools and colleges as an easy variable source of stress in the science class. The most popular battery is a 9 volt type with a tap every 1½ volt that receives banana plugs.
The rare "C" battery form is the bias cell , a button-size miniature battery designed to provide a constant voltage without draining the current. This was briefly popular between 1936 and 1945 because the bias cells were cheaper than the resistor/capacitor bias networks.
In the UK and in some other countries, the "C" battery is known as a "GB" battery (biased grid).
See also
- Battery history
- List of battery sizes
- List of battery types
- Battery Nomenclature
References
External links
- Crosley Radio Receiver Operations Guide 51 Examples of use of A, B and C batteries in the original radio.
Source of the article : Wikipedia
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