Other reasons for using a top cap include improving stability by reducing grid-to-anode capacitance, [9] improved high-frequency performance, keeping a very high plate voltage away from lower voltages, and accommodating one more electrode than allowed by the base. This arrangement substantially decouples the plate and the control grid, eliminating the need for neutralizing circuitry at medium wave broadcast frequencies.

A power supply using a transformer with several windings, one or more rectifiers (which may themselves be vacuum tubes), and large filter capacitors provided the required direct current voltages from the alternating current source. Plotting plate current as a function of applied grid voltage, it was seen that there was a range of grid voltages for which the transfer characteristics were approximately linear. The high voltage applied to the anode (plate) was provided by the "B" battery or the HT (high-tension) supply or battery. An arc can be caused by applying voltage to the anode (plate) before the cathode has come up to operating temperature, or by drawing excess current through a rectifier, which damages the emission coating. The residual gas would cause a blue glow (visible ionization) when the plate voltage was high (above about 60 volts).Due to the high voltage placed on the anode, a relatively small anode current can represent a considerable increase in energy over the value of the original signal voltage.

One of Marconi's needs was for improvement of the detector, a device that extracts information from a modulated radio frequency. Tektronix made a high-performance wideband oscilloscope CRT with a channel electron multiplier plate behind the phosphor layer. or be absolutely anything (standard and special-quality equivalents of the same tube include 12AU7, ECC82, B329, CV491, E2163, E812CC, M8136, CV4003, 6067, VX7058, 5814A and 12AU7A). The raw aluminium materials are cut down and heated to a specified temperature and pushed through an extrusion die at high pressure, before being cooled down, stretched and cut to size, before any additional heat or other treatment. A second electrode, the anode or plate, will attract those electrons if it is at a more positive voltage.Consequently, higher voltage gains from a single tube amplification stage became possible, reducing the number of tubes required.