filament voltage

Earlier you would have not encountered many filament voltages higher than 2.

Once started, filament voltage is reduced to increase operating efficiency.

Switches will need to select the correct filament voltage and pins.

Emission may usually be restored by raising filament voltage.

The valve manufacturers state that the filament voltage should be 1.3V (not 1.4V) if a regulated filament supply is available.

The rough alternating voltage from the magneto was fed to a transformer, to give anode and filament voltages for the valve.

The "A" battery or LT (low-tension) battery provided the filament voltage.

Epiphone then released a head version, correcting these issues and changed the AC filament voltage to DC voltage.

Tube-based transmitters must have power applied in the proper sequence, with the filament voltage applied before the anode voltage, otherwise the tubes can be damaged.

Filament voltage was obtained from Signal Corps alkaline storage batteries and the high voltage was provided by conventional "B" batteries.

In a power scaling circuit, by decreasing just the B+ plate voltage, the cathode bias and screen grid voltage decrease proportionately, while the filament voltage stays constant.

Combo version 1 has front panel stripes that run along the centre of the front panel and has a 4 ohm output only and an AC filament voltage.

There is therefore no need to select the appropriate filament voltage for the particular tube under test, but this equipment will not identify tubes that may be faulty in other (more likely) ways, nor indicate any degree of wear.

The first Epiphone Valve Juniors (version 1) were only combo amplifiers and received only a fair reception, due to such problems as buzzing and hum caused by the AC filament voltage.

The term comes from the days of valve (tube) radios when it was common practice to use a dry battery for the plate (anode) voltage and a rechargeable lead/acid "wet" battery for the filament voltage.

During this time older filament voltage and current "families" were abandoned, so a device name beginning with "A", "B", "C" or "K" and ending in two or more digits is very unlikely to be part of this naming scheme.

The filament voltage to ground is usually at a potential of 30 volts, while the grid voltage at 180-210 volts DC, unless there is an optional electron bombardment feature, by heating the grid, which may have a high potential of approximately 565 volts.

Prior to 1934, Phillips numbers were based on a sequence of one letter to indicate filament current range, followed by one or two digits for the filament voltage, then two digits that gave either the amplification factor (for triodes) or a code beginning with 41 to indicate tetrodes, pentodes and so on.