UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

Refugee · 21st Jun 2018, 9:35 am

I would go for an input of 24 volts as there are more older chips about in thru hole format.
Mains ones have a ready wound primary and are an advantage once you pick up a bit of experience.
Your best early experiment would be an auto-transformer and a UA3842 running from 24 volts. The chip needs 15 volts to start up. I use only the start up sequence to drive an electric fence so that it always pulses every second or so.
If you want to go SMD there are loads of lower voltage parts on old computer motherboards if you are prepared to trawl through the look-up tables for the part numbers.
The manufacturers data sheets are your friends here.

21st Jun 2018, 9:35 am	#2
Refugee Dekatron Join Date: Apr 2012 Location: Worksop, Nottinghamshire, UK. Posts: 5,553	Re: Switched Mode Power Supplies I would go for an input of 24 volts as there are more older chips about in thru hole format. Mains ones have a ready wound primary and are an advantage once you pick up a bit of experience. Your best early experiment would be an auto-transformer and a UA3842 running from 24 volts. The chip needs 15 volts to start up. I use only the start up sequence to drive an electric fence so that it always pulses every second or so. If you want to go SMD there are loads of lower voltage parts on old computer motherboards if you are prepared to trawl through the look-up tables for the part numbers. The manufacturers data sheets are your friends here.