Dropping 12V to 5V using voltage regulator(s)

Using Arduino General Electronics
21

Smajdalf:
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)

PerryBebbington:
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.

22

BabyGeezer:
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.

23

BabyGeezer:
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 ... :astonished:

24

Paul__B:
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.

Paul__B:
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 ... :astonished:

i haven't quite reached those hoarding levels yet :slight_smile:
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")