03-03-2017, 04:50 PM
(03-03-2017, 04:19 PM)pwdrive Wrote:(03-03-2017, 03:09 PM)Nowhere-Man Wrote: You weren't allowed to answer. I knew you would know that one.
Someone else must answer this:
A pentode requires 3 volts negative bias. At this bias and the recommended anode and screen voltages, the anode current is 9 milliamps and the screen is 2 milliamps. What is the value for the cathode resistor? What is the wattage of said resistor?
PS I am exempt as I have Mark's homework already.
I was a naughty boy then....
Here's one for you, a triode hexode osc/mixer is under AGC control, the maximum current drawn by the screen grids is given as 1mA with a voltage of 60 volts on the screen grids, the available HT is 200 volts, what is the approx value of the resistor needed to supply the screen grids with that voltage and at that current and how should that resistor be configured in order to minimise its effect on the mixers anode load selectivity?
There's a connection here with Mark's transistor circuit but the reasons are a bit different.
EDIT: Clue (if required) compare a triode hexode with a triode heptode.
Lawrence.
I figure I could work it out. I know how AGC works. I seem to recall my non AGC diode was grounded out and a grid used instead. The AGC is simply biased in a way only strong signals will drive the anode to positive. Then it will conduct electrons normally to the IF transformer.
This could be a Pandora's box with homework being handed out to those who log on.
Get ready for my next question. It's not a radio question it's an IQ test question that's fun to work out.







