27-01-2017, 04:42 PM
Just touching the theme of filaments Terry raised: Consider the very first radio filaments would run on only 2 volts. That's a good way from 6.3. It suggests to me that such early filaments would be pretty delicate. If they run on just 2 volts to emit electrons, they must be fairly thin. I read that some filaments have to be kept within 10 per cent of voltage and that may possibly include under voltage too (although I'm not sure).
I have heard accounts of some of the suitcase type 90 volt battery HT powered radios needing precise LT voltage (or they are history). I am not sure if the average 1930's battery portables had a bit more leeway.
As to Ohms Law I tend to use the basics often enough not to forget but sometimes find I forget the sums for resonant frequency or even capacitive reactance. I am then forced to look it up and refresh my memory.
I have heard accounts of some of the suitcase type 90 volt battery HT powered radios needing precise LT voltage (or they are history). I am not sure if the average 1930's battery portables had a bit more leeway.
As to Ohms Law I tend to use the basics often enough not to forget but sometimes find I forget the sums for resonant frequency or even capacitive reactance. I am then forced to look it up and refresh my memory.
