Can anyone help me understand the capacitor values on this circuit? They're given in P and Kp. Some of them don't have K or KP, just a number. I was thinking the P denoted Pico farads, but it still doesn't really make sense to me. Say '10kp', is that saying 10,000 Pico farads?
Thanks đź‘Ť
Yes, you are correct. The 'k' stands for kilo an the 'p' for pico. 1k5p would be 1.500pF or 1.5nF. Electrolytes are in µF.
Hugo
It's an antique notation from way back when the prefix n for nano hadn't been invented yet.
Just to add to the confusion: uuF (micro micro farad) was often used in place of pF as well. And when it comes to resistor values, 10M often meant 10K - "meg" was spelled out for megohms.
I'm not sure why someone has drawn this circuit out in the modern age and not just used the modern way of expressing the values
They are drawn as polarized so I would guess they are 1000uF electrolytics.
In the original schematic they are 1000uF 25V electrolytics
https://www.radiomuseum.org/r/armstrong_integrated_stereo_amplif.html
https://www.radiomuseum.org/r/armstrong_integrated_stereo_amplif.html
To be honest, I don't really know it either, it's just my guess that kilopicofarad was used when nanofarad didn't exist yet.
Regarding centimetre as a unit of capacitance, that's the self-capacitance of a spherical conductor with a radius of 1 cm in an infinite vacuum, about 0.9 pF.
I'm learning by the minute 🙂
Here's some more interesting reading:
https://www.vintage-radio.net/forum...5716b2c78cda190836a9c239&p=827112&postcount=4
Hugo
Here's some more interesting reading:
https://www.vintage-radio.net/forum...5716b2c78cda190836a9c239&p=827112&postcount=4
Hugo
Thanks for the correction, I had it upside down.
When mu0 was still 4 pi * 10-7 H/m and the speed of light in vacuum was already 299 792 458 m/s, a sphere with a radius of 1 cm in an infinite vacuum had a self-capacitance of exactly
100 000/(299 792 458)2 F.
That's indeed about 1.1 pF, not 0.9 pF.
You can calculate it from the equations of the speed of light in terms of epsilon0 and mu0 and the equation for the self-capacitance of a sphere.
When mu0 was still 4 pi * 10-7 H/m and the speed of light in vacuum was already 299 792 458 m/s, a sphere with a radius of 1 cm in an infinite vacuum had a self-capacitance of exactly
100 000/(299 792 458)2 F.
That's indeed about 1.1 pF, not 0.9 pF.
You can calculate it from the equations of the speed of light in terms of epsilon0 and mu0 and the equation for the self-capacitance of a sphere.
It wasn't meant to correct you.
Great math, a bit above my head but now I see where we come from.
Hugo
Great math, a bit above my head but now I see where we come from.
Hugo
