الصمام الثلاثي المضخم - الصمامات المتعددة المساري - الصمامات ذات المهبط المسخن

Triode Amplifier - Multi-Path Diodes - Heated Cathode Diodes.. Electronics

Triode Amplifier

You can see in Figure (89) that there is an audio signal at point S and that the resistor M completes the network circuit, so the cathode current passes through the resistor M2. If we want the control network voltage to be -2 volts with respect to the cathode K, the resistor M2 must be chosen so that it leads to a voltage drop of 2 volts. As for the capacitor S A, it works with the resistor M2 as a gate to pass all the frequencies to be amplified.

If no signal is connected to point S, the network bias becomes -2 volts and the anode current becomes 6 milliamps. If an audio signal is connected to point S and its peak voltage is 2 volts, the network voltage fluctuates between 1 volt and 3 volts, and the anode current fluctuates between 8 and 4 milliamps. The voltage drop across the resistor M3 placed in the anode circuit also fluctuates according to the increase or decrease in the anode current itself. Thus, we ultimately obtain an amplified signal through capacitor S2. It is also noted that the capacitors used isolate this circuit from the rest of the other circuits (90).

89 - Thermoelectric triode amplifier.
90 - Isolation of DC circuits using coupling capacitors.

Multi-path valves

. If an additional grid S2 is placed between the control grid S and the triode anode (91), and the voltage of this grid is positive, we notice that the intensity of the anode current does not depend only on its voltage, but also on the voltage of this grid. The reason for this is that when electrons collide with the anode, some of them, called secondary electrons, bounce back to the positively charged grid, while the "blocking grid" S3 is tasked with obstructing this process. By adding this third grid, the tetra-diode turns into a pentagon. As for the plates located between the blocking grid and the anode, they obstruct the flow of electrons from the anode to the blocking grid itself, and it is possible to control the path of electrons using more than one grid as in the heptagonal diode. This last diode has two amplification circuits (92), in which the signals applied to S A and S control the flow of electrons, and in this case the two grids S2 and S4 work as blocking networks for S3 and S5. 91 - The blocking network in pentagonal and quadruple valves. 92 - Two other types of valves with multiple electrodes.