Figure 19, eh, Standard Resistance Coupled Amplifier Stage. B, Amplifier with Bootstrapped Load Resistor in the Plate Circuit. Description of Part eh of the figure begins here. The hot input terminal goes directly to the grid of a triode. The grid also goes through a 1 meg ohm resistor to ground. The cathode goes through the parallel combination of a 1.2 k ohm resistor and a 100 u f capacitor to ground. The plate goes through a 100 k ohm resistor to a point labeled plus 250 volts. The plate goes through a 0.1 u f capacitor to the output. The output goes to ground through a 1 meg ohm resistor. This completes the description of part eh of figure 19. Description of part b of figure 19 begins here. The hot input terminal goes directly to the grid of a triode. The grid also goes through a 1 meg ohm resistor to ground. The cathode goes through a 750 ohm then a 240 ohm resistor to ground. There is a 470 u f 25 volt capacitor in parallel with the 750 ohm resistor. The plate goes through a 100 k ohm resistor to the source of an I r f 820 m o s f e t. The drain goes to plus 400 volts. The 400 volt line also goes through an 18 k ohm 1 watt then another 18 k ohm 1 watt resistor to the cathode of a 100 volt 5 watt zener diode. The anode goes to the cathode of another 100 volt 5 watt zener and the anode of this zener goes to the cathode of yet another 100 volt 5 watt zener. The anode of the last zener diode goes to ground. There is a 22 u f 450 volt capacitor in parallel with all three zeners. The junction where the cathode of the top zener, the plus side of the 22 u f capacitor, and the 18 k ohm resistor all come together goes through a 1.5 meg ohm then a 150 ohm resistor to the gate of the Mosfet. A 0.047 u f capacitor connects from the junction of the two resistors to the plate of the tube. The plate also connects through a 0.1 u f capacitor to the output. A 1 meg ohm resistor connects from the output to ground. This completes the description of part b of figure 19.
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