Mutual characteristics for variable-μ and short grid base pentodes. It is often desirable to be able to control the amplification of a valve, either manually or automatically (as in the case of AGC in radio receivers).

Feb 8, 2009 · I included measurements for AGC behaviour, detector performance, and stage gain for the original radio and several variants with improved detector gain and AGC compression. In one of the circuit variations, I got the detector gain boosted to over 5, and AGC delay improved compression for signals in my urban home area.

The 12K7GT variable-mu screened pentode was designed in the 1940's for intermediate frequency amplifiers in superhet receivers where the stage gain was controlled by the application of negative bias on the grid. That bias or AGC voltage was derived from the …

Inherently the technology leads to more linear sharp cut off pentode characteristic. This means that AGC/AVC must be implemented by g2 or g3. Limited almost linear gain control, especially at lower anode currents is possible in Pentode mode by varying g3.

The 30C17 is a triode variable-mu pentode designed for television frequency changer use. When introduced it was the first variable μ TV frequency changer to be available in the UK. The frame-grid variable-mu pentode enables the AGC line to be applied to the mixer and avoid overloading on strong local signals.

Jul 8, 2018 · Can anyone tell me if it is possible to use a rod pentode in a Transitron /miller timebase as used in scopes tv,s etc.

Jan 16, 2012 · It is the purpose of the AGC control to keep the non-inverting voltage gain from G3 to G2 at 3x to satisfy the 1/3 loss through the Wien circuit. This means that the gm of the tube will be kept constant by the AGC loop, despite any emission variations.

The AC2/PenDD is a double signal diode and output pentode. The high mutual conductance of the pentode was designed to allow the single valve to operate as detector, AGC rectifier and the audio amplifier driving the speaker.

Pentode valves are most often used in IF amplifier stages. The cathode decoupling capacitor may have a resistor inserted in series with it in order to reduce the gain. This would be needed in the case of high gain amplifiers using more than one valve in a single IF amplifier stage.

Graphic symbol representing a pentode of the indirectly heated cathode class Electrodes, listed from top to bottom: anode, suppressor grid, screen grid, control grid, cathode. A pentode is an electronic device having five electrodes.