Reducing voltage of laptop power supply...

[John Larkin]

On Tue, 18 Apr 2023 10:34:53 -0000 (UTC), Jasen Betts
<usenet@revmaps.no-ip.org> wrote:

On 2023-04-16, Clive Arthur <clive@nowaytoday.co.uk> wrote:
On 14/04/2023 14:59, Lamont Cranston wrote:
I have a Toshiba 3.4A, 19V laptop power supply that I want to reduce to 12V.
Is it as simple as finding a 19V zener and changing it to a 12v zener?
Thanks, Mikek

Given that 19V is a *very* common laptop supply voltage, I wouldn\'t be
surprised if they used a fixed 19V supply chip.

with a built in opto-isolator?

Some flyback controllers sense the flyback voltage and don\'t have the
optocoupler. Saves money and is usually good enough for a wall wart.

 

[Lamont Cranston]

I\'m trying to keep everything food grade. So, the buckets that were food buckets. The heaters are, not food grade are kept from the water, so should not contaminate. I laid some thin copper tape, put the heater on and covered it with another piece of copper tape. I offset the twp pieces of tape to get more area, but I\'m not happy with the heater reaching 147*F. I think I may need more heaters (or a different type) to get the required Wattage but a lower temperature.
My original plan was to use a 5 gallon bucket and foam in a 3.5 gallon bucket for insulation, but I decided against it as, I didn\'t see a way, to keep it food safe. Actually, now that I have the two buckets that seem to be a good solution, I could put this all in a foam insulated 5 gallon bucket. Maybe something for the future development.
Mikek