Output tube bias circuit

It can be known from the input characteristics of the transistor : when the input voltage is < 0.6V, the transistor is not conductive, and this section is called
the dead zone. In the Class B push-pull output circuit, since the static operating point Q is set at b=0,
neither tube A nor tube B can conduct when the input signal voltage is between +0.6V and -0-6V, and the output The signal is bound to be distorted. This type of distortion
is called crossover distortion, as shown in Figure 1-16. In order to solve the crossover distortion problem, it is often necessary to set up
a static bias circuit for the output tube when designing the circuit. The bases are biased at about ±1V respectively, as shown in Figure 1-17. In this way,
the output circuit of the amplifier is actually no longer a pure Class B, but is in a Class A and B working state.
    Push-pull output bias circuits generally use resistor bias, diode bias, transistor bias, and composite bias
with an additional thermistor . The diode or thermistor in the bias circuit plays a role in temperature compensation.