grid bias

Grid bias batteries are still manufactured today, but not for radio use.

Grid bias is most often provided by a cathode resistor.

Additional voltages were sometimes also required for grid bias.

Triodes: triodes cut off when applied grid bias is too low.

This concept is called grid bias.

Early sets used a grid bias battery or "C" battery which was connected to provide a negative voltage.

As grid bias is increased, more of the electron current is repelled, resulting in a smaller current at the plate.

Grid bias could also be achieved by using an applied grid voltage in addition to the control voltage.

Valves that require a negative grid bias can be used by putting a positive DC voltage on the cathode.

GB, grid bias or C battery.

Under steady state conditions (no audio driven) the stage will be a simple RF amplifier where the grid bias is set by the cathode current.

For vacuum tubes, a (much higher) grid bias voltage is also often applied to the grid electrodes for precisely the same reason.

In Britain and in some other countries, the "C" battery was known as the "GB" (grid bias) battery.

This is often exploited in R.F. amplifiers where an alteration of the grid bias changes the mutual conductance and hence the gain of the device.

Grid bias is a DC voltage applied to electron tubes (or valves in British English) with three electrodes or more, such as triodes.

Some firms make a related tube called an E34L which is rated to require a higher grid bias voltage, but which may be interchangeable in some equipment.

The resistor R1 sets the grid bias, both the input and outputs are tuned LC circuits which are tapped into by inductive coupling.

Another weakness is that none of his Audion schematics denoted the provision for any sort of "grid bias", an essential feature of any true vacuum triode operation.

The mean anode current for a vacuum tube should be set to the middle of the linear section of the curve of the anode current vs grid bias potential.

Later systems using vacuum tube oscillators often used the output from a carbon microphone to modulate the grid bias of the oscillator or output tube to achieve modulation.

The grid bias produced by the grid leak across the biassing grid leak resistor, plus the typically non-linear characteristic of the valves chosen, result in a non-linear rf amplifying stage.

This so called grid bias can be derived, either capacitively, conductively or inductively depending on whether the oscillator is a Colpitts, Hartley oscillator, Armstrong tickler or a Meissner.

Note that the above basic schematic is essentially the same as in the patent drawing, except that the tube is replaced by a J-FET, and that the battery for a negative grid bias is not needed.

In the days of valve radios which used batteries designed specifically for vacuum tubes, there was a nine volt grid bias battery or (US) 'C' battery which had tappings for various voltages between 1.5 and 9.

The resultant radio receiver required a 90 volt HT plus a 4 volt LT (A and B) battery (the HT battery provided not only 82.5 volts for the HT but also two grid bias supplies at -1.5 volts and -7.5 volts).