hi, all,
I am reading an article by Rod Elliott titled "A Simple Capacitance Multiplier Power Supply For Class-A Amplifiers", located here:
Capacitance Multiplier Power Supply Filter
I have a question regarding the purpose of the 12k resistor in Figure 3:
The text says the following about this resistor, but I don't get it:
"The resistor to ground stabilises the circuit against variations in transistor gain, but increases dissipation slightly. This is done deliberately to ensure that there is sufficient voltage across the multiplier to allow for short term variations."
How this resistor to stablize the gain? e.g., what's the cause of the variation of the gain, and how this resistor to cure it?
thanks.
I am reading an article by Rod Elliott titled "A Simple Capacitance Multiplier Power Supply For Class-A Amplifiers", located here:
Capacitance Multiplier Power Supply Filter
I have a question regarding the purpose of the 12k resistor in Figure 3:

The text says the following about this resistor, but I don't get it:
"The resistor to ground stabilises the circuit against variations in transistor gain, but increases dissipation slightly. This is done deliberately to ensure that there is sufficient voltage across the multiplier to allow for short term variations."
How this resistor to stablize the gain? e.g., what's the cause of the variation of the gain, and how this resistor to cure it?
thanks.