Here is yet another non radio project from the past.
But it is electronics from the 1970's and what you do to fix a perceived problem.
I am glad I put the project in a box under the bench and not in the bin.
Still clearing out junk from the workshop and when I found this device it took me some moments to remember what the hell it was.
Must be getting old!


Cheers, Fred.

Yes I will get back to radios soon.............................

12 volt positive earth charging regulator

There is nothing like diversity to keep the mind active. Nr 2 Oscilloscope (BWD) decided to have a hissy fit & loose the trace around midnight, something else to fix. I was working on an OK1 sig gen that had all its coils wires broken off. Believe it or not its book was inside it; rather vague (full of holes) as it did not have much info on the coils. However, if you knew enough to be messing with one of them you could workout which were the resonant coils & where they went. of course phasing the coils is a requirement or it will not run.

Took the tractor for a nice drive in the sunshine, to do a delivery & then turned to the lawn with the push mower. I should get some 410 cartridges to shoot the mozzies'': Big this year, think they have been biting joggers on steroids.

So after pacifying the back, its back to welding & the next mowing exercise, after that will involve a tractor. After that I may get back to radios.

Wednesday looks like rain, so I might get at a commercial radio repair job on a chassis that needs a birthday.

No stopping here, its normally 16Hrs+ of daily entertainment


Marc

Document uploaded.

I rigged a Lucas 12v generator up to a motor with a belt drive and ran at 3000 RPM with both original and my SS regulators.
This part 2 article shows some field waveshapes and voltages with a 15 amp load applied to the generator.

Yes I know still not a radio project but interesting.

12 volt positive earth charging regulator - Part Two

Cheers, Fred.

Document uploaded to Post 4.

Fred.

Your first calculation looks good ---I see roughly 31.25 Hz

The second calculation gives me 80 Hz.??

Your time-frequency conversion is OK.

Something seems wrong with the 40/5 x 10mS. Without seeing your CRO graticule I cannot help much more.

Disclaimer: I'm drinking lights (low alcohol beer) while doing these calculations, apologies in advance if I've cocked up.

Yep, thanks BBV.
I could never get my head around time /sweep/hz calcualtions!
Now I cannot see where the 5 comes in myself.

There is about 40 alternations across 10 divisions or 4 per one 10ms section.
Thats 0.4 ms per alternation?
My head hurts more!!
Somewhere around 80 Hz looks like, what it looks like.
Fred.

Fred,

You are on the right track with your second equation. 80 Hz is 12.5 mS per cycle. That's where your '12' came from.

I struggled for years with time/Hz calculations until I latched onto 50Hz = 20mS as a quick easy reference.

1 second of time divided by frequency gives us the time per cycle:
Therefore 1sec/50Hz = 0.020 seconds per cycle (20mS)

Working the other way:

1 second divided by time of one cycle gives us frequency:
Therefore 1/ 0.020 seconds (20mS) = 50 Hz

I wonder if your oscilloscope ( I called it a CRO yesterday--light beer talking) can resolute to one cycle readout? That would save you a
lot of extra mucking around which is probably where the confusion occurred.

I still use a CRO so I don't know anything about digital oscilloscopes, but surely they can display one cycle?

Ta, I'll hang onto that 20ms = 50Hz as a mental guide.

Funny how a persons brain is blind to some simple things.
I just cannot get the time/cyclic concept into my head.

I guess these simple things are like learning to tie your shoe laces!
you either get it or dont.

Then again I did not learn to speak or write until really late and found there was a purpose for them.
Thats why I always wound up in the dumb classes early on at school.
Once I found out the purpose of reading writing and speaking it only took a couple of week to sort them out and I could go into a normal class!

Fred.