I have a 12v DC power source and need to adjust the voltage on

>>1229286
rheostat

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>>1229288
Could I use a standard AC light dimmer switch or would this not work?

>>1229291
No...

>>1229286
>being this unspecific
GUYS I NEED VEHICLE W/ >=1 WHEELS WHAT U RECOMMEND?

>>1229328
>12v DC power source and need to adjust the voltage on the fly from 1v to 12v

You too stupid to work within these perimeters?

>>1229286
Buy something like this:
https://www.aliexpress.com/item/XL4016-voltage-regulator-external-potentiometer-buck-module-high-power-8A-XH-M405-DC-DC-regulator-module/32804553813.html?ws_ab_test=searchweb0_0,searchweb201602_2_10152_10065_10151_10068_10171_10084_10083_10080_10304_10307_10082_10081_10301_10110_10137_10111_10060_10112_10113_10155_10114_10154_10056_10055_10054_10312_10313_10059_10314_10315_100031_10099_10078_10079_10103_10073_10102_10052_10053_10142_10107_10050_10051,searchweb201603_2,ppcSwitch_5&btsid=75619a36-c95b-44ce-b5e8-9cd30161c099&algo_expid=89d09833-002b-4ec8-9098-3362ba464be6-14&algo_pvid=89d09833-002b-4ec8-9098-3362ba464be6&transAbTest=ae803_1

>>1229286
LM317. check out their example circuits on the datasheet

V= I*R

Just figure out how much resistance you need to take it from 12v to 1v. Buy a rheostat (variable resistor) and wire it up. Make sure the wattage rating is higher than what the supply is putting out.

>>1229349
Yes.
>output current
>impedance
>stability
>sinking capability
dumbass.

>>1229363
The problem was already solved before you got here...

>>1229366
was it? any of the solutions posted might be total crap for OPs application

This is a typical bait thread. The only purpose is to generate replies.

A non-regulated rheostat would work fine if you're only using very small load currents, a linear regulator like LM317 will work for medium loads, and a variable buck converter is what you'll need for high loads. Though chances are a 12V motor PWM speed controller will do what you want.

>>1229286

Hey! I dated that girl in my high school!

>>1229286
What's the input impedance?

>>1229358
Not an electronics pro but wouldn't that just adjust the amps since OPs power supply is 12V

>>1229354
LM317's don't go below 1.3Vs iirc.

>>1229637
There is a voltage drop across a resistor.

>>1229286
>I have a 12v DC power source and need to adjust the voltage on the fly from 1v to 12v. How do I build a device to do this using only parts salvaged from standard consumer electronics (tvs, radios, computers, etc)?

reuse a couple of resistors to create a voltage divider with 1V output for a 12V input. Then, find a double-pole single-throw switch, and just use it to switch between your 12V and 1V sources. you're welcome.

>>1229647
Most are under the assumption that OP wishes to also have 2-3-4-5-6-7-8-9-10 and 11 volts available too, hence the rheostat answer...

If it's salvaged parts he wants to use, he could probably make a buck converter if he tried hard enough.

>>1229785
Everyone seems to assume whatever op is powering has an infinite input impedance which to me is a much more pressing issue

I'm not a pro, but wouldnt a buck boost converter work?
Maybe follow by a common emitter amplifier or some shit to drive the output?

>>1230009
Or a significantly high input impedance, in the case of the voltage divider.

>>1230010
He wants to make it out of salvaged parts, but it should be possible, especially using the components from the consumer electronics' logic-level power supplies. I'm not sure if you need the boost part as well as the buck part since it would be converting 12V to 12V, but if he puts a linear regulator afterwards to smooth out the waveform then I guess it's a must for him to boost the voltage to 14V and regulate it down to 12V. It's the bottom-end voltage that I'm not sure about, though he states that it requires a minimum of 1V, not 0V, so it should be fine provided he uses a good enough regulator.

>impedance
>12V DC

>>1230062
Impedance is still a valid term, though a little redundant, as any reactive parts will either be 0 (or 1/0, in parallel).

>>1230078
if you have a regulator there is actually reactance.

>>1230062
educate yourself

>>1229286
gonna have to be a lot more specific. Do you need to regulate is dynamically based on other parameters, or can you do this yourself and just feel it out.

>>1230154
A regulator gives some capacitance to ground independently from its regulating caps, right? Isn't that just because of its transistor(s)?

>>1230163
The feedback loop doesn't react instantaneously (obviously), making the supply slightly inductive.

>>1230170
Oh, so it's virtual inductance from active circuitry? That's pretty neat, I never considered that. Is that the reason the suppression caps are required in the first place? I'm surprised they aren't just built in to linear regulators these days.

>>1230173
the output caps provide for load transients, suppress switching noise and regulator overshoot (and hence also stabilize the feedback loop), or fuck the stability of the regulator due to resonance

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>>1229286
>it isn't a gif

>>1229328
a horse

>>1229286
>not just using a DC output model train transformer

>>1229291
If you can't differentiate between and AC and DC you probably shouldn't touch electronics.

Use a rheostat, like a volume controller or something similar if you're salvaging.

t. Electrician

>>1229374
niggas addicted to (you)s

>>1231510
Well if the dimmer generated its own PWM frequency instead of using the AC frequency then it would probably work, not to mention the workings of a light dimmer being somewhat black magic.

>>1229286
I just built a model train controller around this motor driver. It worked well:
http://www.allegromicro.com/~/media/Files/Datasheets/A4973-Datasheet.ashx

Or for simplicity just use a rheostat aka potentiometer aka pot.

>>1229354
That's a terrible idea. Going from 12V to 1V with any significant current draw will burn loads of power in the regulator. Without a beefy heatsink it'd be fried. Without knowing what kind of current the load is drawing I'd avoid recommending linear regulators.

>>1229286
OP what you are looking for is a buck regulator. Designing one is way over your head and not something I'd recommend with salvaged parts. You can find premade buck converter modules cheap on eBay. Get one that fits your specifications (12V input, variable output with minimum 1V or less.) There should be something out there that will work.

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>>1231752
>Designing one
Why would he need to do that? Surely he could make a buck converter from salvaged parts that were originally in use as a buck converter, and modify it a little with a salvaged potentiometer to vary its reference voltage, all from online schematics. Of course the desoldering would be a nightmare. OP might actually be able to use a DC dimmer if he just needs variable power output regardless of waveform, which might mean less desoldering, less complex understanding, but more part-hunting unless one of his scrap boards has a DC dimmer on it. Is that how LED backlights are dimmed?

But in all honesty I think OP's thread is B8, pic sort of related.

>>1229639
That's why you set it between 1.4V & 13.4V output and then stick a pair of diodes in the output to drop the extra 1.4V.

>>1230009
>>1230058

doesn't matter. if the input impedance is known, it's easy to design for. Opie's pic doesn't imply he wants an adjustable bench supply.

>>1230728
>>1229286
i kno rite? the only time i've ever hoped for a gif

find or buy two 555 timer chips, then build a shitty PWM device. Use the first as an astable monovibrator to make a pulse train, or find some kind of suitable clock module instead. Feed that into the second, and built it as a monostable multivibrator. Control the pulse length of the second one with a potentiometer, giving you your throttle. feed the output into a bigass transistor and use that to switch your 12v.

>>1233606
this

tried and true method for generations of diy'ers

555 is epic due to its simplicity

>>1229286
Just buy a cheap buck converter on ebay