Re: Small/cheap/easy 3V power supply

On Wed, 31 Jan 2007 23:14:11 +0000, Chris Jones <lugnut808@xxxxxxxxxxxxxxxx> wrote:
Jan Panteltje wrote:

On a sunny day (Wed, 31 Jan 2007 11:30:25 -0600) it happened
Ignoramus20785 <ignoramus20785@xxxxxxxxxxxxxxxxxxxx> wrote in
<XKudnRcdNqmsT13YnZ2dnUVZ_qninZ2d@xxxxxxxxxxxx>:

On 31 Jan 2007 17:14:53 GMT, John B <spamj_baraclough@xxxxxxxxxxxxxxxxxxx>
wrote:

A 1N4001 will drop .7V for you.


This is VERY smart. I love your idea. I have about 100 of them, or
similar diodes, if not more. Now it looks like a one hour project
(time mostly spent making sure that the wire from wall wart is
securely fastened to the chop saw).

Thank you!!!!!!!!!!!

Cool idea :-) But 5% mains voltage change will be 5 V.....
I'd personally get a small 9switching) AC/DC adapter (very small ones
exist, and either combine the cables, or mount it on the tool.

He was not proposing dropping the mains voltage with diodes, he was
proposing using a nominally 3.7V output from a Wall-Wart thing and dropping
0.7V with a diode. That sounds much more sensible.

Yes, that is my plan.

I don't know how sensitive the laser module is to the supply voltage. If it
is not critical (as one would hope since it is battery powered) then the
above solution should be OK, otherwise it would be better to use a 3V LDO
regulator, but these are not all that common/cheap compared to a LM317.
The problem with the LM317 is that it needs about 6V input to put out 3V
reliably. If he has a 6V wall-wart and a LM317 then that would be ideal.

I think that it ought not be too sensible, being battery powered.

i
.

Relevant Pages

  • Re: Small/cheap/easy 3V power supply
    ... He was not proposing dropping the mains voltage with diodes, ... I don't know how sensitive the laser module is to the supply voltage. ... If he has a 6V wall-wart and a LM317 then that would be ideal. ...
    (sci.electronics.design)
  • Re: Need help with surface part ID and finding a schematic
    ... I fix surface mount power supplies for a living and still I can't recognise ... instance the pink non-surface mount 15/16 items are diodes but could be any ... a triac or whatever. ...
    (sci.electronics)
  • Re: quick question on AS-2518-54 Bally Rec board what are CR5-CR8?
    ... Scorching under these diodes is common for the -54. ... when I repair them (6 Amp) and mount them up off the board a bit to ... Steve Kulpa (cargpb10) ...
    (rec.games.pinball)
  • Re: Small/cheap/easy 3V power supply
    ... similar diodes, if not more. ... I'd personally get a small 9switching) AC/DC adapter (very small ones exist, ... and either combine the cables, or mount it on the tool. ...
    (sci.electronics.design)
  • Re: diode-connected transistors
    ... Terry Given wrote: ... I believe at's actually avalanche breakdown. ... > sometimes I use them as diodes. ... mount in a thermally meaningful way). ...
    (sci.electronics.design)