cantgetnosleep
Well-known member
Hello everybody,
I've been lurking around for the last few weeks enjoying the posts and getting excited about learning more electronics and doing some DIY. I've really enjoyed reading the posts on this forum. There seems to be a minimum of b.s. and a maximum of helpful content around here, which is pretty nice. Anyway, I found a copy of the Audio Cyclopedia, which was expensive, but awesome, and I have been digging into it. I love it, in part, because it explains tubes. But, of course, now I've got a question, and it's really basic.
Simply stated - In a two-stage triode amplifier, why does increasing the plate load resistor increase the voltage gain of the amplifier?
Or to quote tremaine - "To obtain a large voltage gain in a resistance coupled amplifier stage, the plate-load resistor must have as large a value as is practical."
This seems counter-intuitive to me because the higher the plate-load resistance is, the less current will flow through the plate and the greater the voltage drop across the resistor. This means that the voltage at the plate is lowered as the resistance increases. This implies (to me) less gain as resistance increases becuase less voltage is available at the plate.
Can somebody please explain where I went wrong with my reasoning?
For those of you that have the tremaine book (2nd edition), I'm looking at figure 12-1A.
Thanks - Andrew
I've been lurking around for the last few weeks enjoying the posts and getting excited about learning more electronics and doing some DIY. I've really enjoyed reading the posts on this forum. There seems to be a minimum of b.s. and a maximum of helpful content around here, which is pretty nice. Anyway, I found a copy of the Audio Cyclopedia, which was expensive, but awesome, and I have been digging into it. I love it, in part, because it explains tubes. But, of course, now I've got a question, and it's really basic.
Simply stated - In a two-stage triode amplifier, why does increasing the plate load resistor increase the voltage gain of the amplifier?
Or to quote tremaine - "To obtain a large voltage gain in a resistance coupled amplifier stage, the plate-load resistor must have as large a value as is practical."
This seems counter-intuitive to me because the higher the plate-load resistance is, the less current will flow through the plate and the greater the voltage drop across the resistor. This means that the voltage at the plate is lowered as the resistance increases. This implies (to me) less gain as resistance increases becuase less voltage is available at the plate.
Can somebody please explain where I went wrong with my reasoning?
For those of you that have the tremaine book (2nd edition), I'm looking at figure 12-1A.
Thanks - Andrew