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### Topic: Dropping 12V to 5V using voltage regulator(s) (Read 824 times)previous topic - next topic

#### BabyGeezer

#15
##### Dec 08, 2018, 01:30 am
No, I meant a USB phone charger that plugs into the cigarette lighter hole in the dashboard of a car.
You just asked for a 12>5volt/1A regulator.
...
ahh yes, those are common enough indeed - but i've never had one.

might be worth getting if it had a good enough rating, Thanks !
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#### Paul__B

#16
##### Dec 08, 2018, 04:19 am
I would never buy one new but ... Garage sales!

#### BabyGeezer

#17
##### Dec 08, 2018, 04:58 am
I would never buy one new but ... Garage sales!
better yet, old car in a junkyard ?
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#### Smajdalf

#18
##### Dec 08, 2018, 08:18 am
obviously they should be properly rated, my stock of resistors are just the 1/4W ones though
You may use several resistors in parallel to get more power dissipation. It won't be nice but it is usable to get it working ASAP.
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#### PerryBebbington

#19
##### Dec 08, 2018, 11:13 am
Collect wall worts. Any electronic equipment being thrown away keep the wall wort. Ask friends and family to save them for you too. That way you will always have a suitable power supply for pretty much anything.

#### BabyGeezer

#20
##### Dec 08, 2018, 12:10 pm
You may use several resistors in parallel to get more power dissipation. It won't be nice but it is usable to get it working ASAP.
i see - so, to calculate Ohm's Law - i'd then divide the effective current (for the wattage) by the number of resistors in parallel ? (not forgetting that resistors in parallel also drop the total resistance)

Collect wall worts. Any electronic equipment being thrown away keep the wall wort.
...
yep, that's what i've been doing - 5V, 9V but just the one 12V.
and they are all under 1000mA! (i have 500mA, 600mA and 900mA !!)

i should repurpose an old USB cable - i have a phone charger (1000mA) that has a USB socket.
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#### PerryBebbington

#21
##### Dec 08, 2018, 12:15 pm
Yep, that's what i've been doing - 5V, 9V but just the one 12V.
and they are all under 1000mA! (i have 500mA, 600mA and 900mA !!)

I should re purpose an old USB cable - I have a phone charger (1000mA) that has a USB socket.
OK, good!

Well, one of the delights of electronics as a hobby is finding new uses for old things, or getting things to work in ways the manufacturer never intended.

#### Paul__B

#22
##### Dec 08, 2018, 12:20 pm
i should repurpose an old USB cable - i have a phone charger (1000mA) that has a USB socket.
Which is a bit old.  Most are now rated at 2.1 A (to match the iPad).

Going price should not exceed \$5.  Purchased locally (as eBay stuff is not trustworthy).

I have a 52l plastic storage bin full of power supplies (but not all are in that bin and not all are lightweight switchmode).  Trouble is, getting to it in the stack ...

#### BabyGeezer

#23
##### Dec 09, 2018, 04:16 am
Which is a bit old.  Most are now rated at 2.1 A (to match the iPad).
i'm nowhere in the circle of iProducts - the phone charger is actually new, for a chinese brand and that is 1A only.

it's the USB cable that is old, still with a type A plug at the other end.

I have a 52l plastic storage bin full of power supplies (but not all are in that bin and not all are lightweight switchmode).  Trouble is, getting to it in the stack ...
i haven't quite reached those hoarding levels yet
but i do find the older adaptors that i've "stocked" are quite useless when it comes to the crunch, including a cheapo one supposedly rated at 1000mA but doesn't seem to be able to provide it. (i have an INA219 module otw to start getting proper numbers on my "inventory")
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