I drew a schematic of a 60's automatic lead acid battery charger. Needs to be checked
for errors, if you please. I had the wrong polarity on the power diodes last time I tried
it. Got two tall columns of smoke at the alligator clips, lots of fun; once is enough. I re-
placed the SCR after that. (Attachement)
tks.

 

first of all make the font's bigger, most of the members have a hard time reading small and tiny fonts.
secondly where is the attachment

 

A 60 second charger? That would be a lot of amps.. No wonder you got pillars of smoke. The electrolyte would boil away.

 

My first thought was he meant a 1960s design, which I though was a bit odd...

 

Its there when I click on the paper clip, lets see...

 

Hello,

The schematic is still not attached.
This is the text from the FAQ about attachments:

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Succes,
Bertus

 

here it is...

 

Hello,

I merged the threads, so the schematic is combined with the question thread.

Typical is that the circuit is "upside down" using the PNP transistors.
This was used a long time ago.

Bertus

 

No wonder you have trouble, that is not even the symbol for the SCR, Who drew that any ways, does he know electronics and it's symbols.

 

It looks like a manufacturers diagram. Older gear often had a paper diagram stuck inside one of the covers.

It is difficult to follow due to the odd component arrangement, and the two PNPs look to have been drawn upside down - the emitters should be to positive.

I think the idea is that the MPSA92 should be on (providing gate current to the thyristor) until the battery voltage reaches a certain point, then it shuts down and only fires occasionally to maintain the float charge voltage.

I've seen chargers designs using the same principle many years ago, but this schematic is dire..

 

R!F the font was set that way when I got on this library computer,didn' notice.
Retched Does it look better with the aposthrophe ? Ihad put one in there guess I didn'it the key hard enough.
Rjenkins Maybe its an antique
Bertus I took "browse" as a mere suggestion having the schematic ready on the desk top.Not. got to use it. And thanks for merging the threads.
R!F Re: scr This is a second symbol I found. there is some inconsistency in symbols especialy over many decades .I copied from books from 1930 and up The trans former is from the 40' and 50's for example
TO ALL : no experience no degree, green etc. quote " I drew ... needs correction"
RJenkins "looks likea diagram " is a wonderfull compliment to me, really
The NPN upside down thing worries me,
maybe I was making the diagram read left to right. I suppose a proper corrected copy would be asking to much . back to the drawing board .tks for your patience, I learned a lot