12v To 1.5 V Resistor

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How to cutting downward 12 volts to one.v volts

• Thread starter John1397
• Start date Jun 21, 2018

I know ane tin can use a LM317 to cut 12 volts dc to ane.five volts but can one employ resistors? I have a wall clock that runs a modest motor to current of air leap and it powered by a c bombardment you can run on more voltage without out harm to any thing as it merely run for i second every 2 minutes. I tried a 30 ohm resistor merely information technology still must be to much voltage as when information technology winds upward the spring it information technology goes to far causing it non to release the switch when unwound. Practice these small brush type dc motors draw a abiding load from startup thru full speed running? tin't imagine these motors draw many amps running off a c battery. I was also wondering when you lot employ a resistor to cut voltage downward do you likewise lose amps?

Answers and Replies

Do these small brush type dc motors draw a constant load from startup thru full speed running?

No.
Current is in proportion to torque and vice-versa.
Speed is in proportion to voltage.

I was as well wondering when yous employ a resistor to cut voltage down practice y'all as well lose amps?

Yes you do.

Are you using this in a car ? Or using a "Wall Wart" ?
If the latter look for a iii or five volt phone charger. It won't overspeed your motor so severely.

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I know one can apply a LM317 to cut 12 volts dc to 1.5 volts simply can one use resistors?

as @jim hardy said, no

do as he suggested and apply a 3V wall adaptor and you could put a couple of 1N4001 diodes in series with the positive wire and that will drib ~ 1.4V and yous will exist shut to spot on for your 1.5V requirement

Dave

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Last edited: Jun 21, 2018

I seemed to got information technology to work just went up to 60 ohm resistor used 10 watt only thing I am not certain of is should 1 put oil on these wire castor as this would make them wear less but probably become dirty faster is this not right? I am running this off house solar ability that is why I wanted to do this as take lots of free solar power.

If you have 12V then a neat solution would be 1 of those buck converters that plug into the cigarette lighter and drop the 12V down to 5V USB. You lot could then feed this into the LM317. Less wasteful than just resistors.

Less wasteful than simply resistors.

As already noted, you cannot use "but resistors" anyhow

the OP is going to find that the voltage will non exist stable with his resistor

How much electric current does the motor draw?

There are plenty of DC to DC converters on eBay that will turn 12v to 1.5v.

I am running this off house solar power that is why I wanted to practise this as accept lots of free solar power.

Solar ability and running off of the grid is all near efficient conversion of energy. The advice yous are getting about switching DC-DC power converters is good. This is a adept projection to learn more about those, IMO.

I am running this off house solar ability that is why I wanted to do this as have lots of free solar power.

I know this is a unlike topic, only since yous brought it up, that's a very surprising thing to say. Didn't yous pay for the solar organization? A lot? Generally solar systems are very expensive so maximizing efficiency, as @berkeman said, is typically critical to the economic success of the organisation. We'd be delighted to help discover ways to maximize the economics of your organization if you want.

Ahhh, solar. Then that's why 12 volts...

You might take apart one of those solar k lights.
They typically have a single rechargeable AA cell .You'll relocate that to the rear of the clock. AA and C are same length so you can brand it fit , or get a new holder..
Run small wires out to the photocell that you've salvaged and ingeniously mounted where it gets full sunday. Doorbell wire volition be perfect, telephone wire would work too.

It's low voltage so there'due south non a lawmaking consequence, just keep it abroad from any AC mains wires. Don't share conduits or pass-throughs with them.

EDIT - And don't brand an unintended lightning rod of it ...

one-time jim

Last edited: Jun 22, 2018

You might take apart one of those solar yard lights.

Great suggestion. Y'all can purchase those things for at little equally $1 each.

When they said resistor is not going to work that sure was right I had to become back to the style information technology was using carbon c battery simply matter I added that seems to piece of work is a put a 10 watt 600 ohm resistor in between 12 volt dc and battery it only raises battery voltage .01 of a volt I think this should be perfect every bit battery voltage with 12 volts applied thru resistor was at ane.61 volts. I tried 1000 volt resistor didn't seem to raise battery voltage and 300 ohm raises battery voltage .02 of a volt. Once in a while it stops I am always thinking information technology is the motor brushes not making contact but this does accept a magnetic reed switch I might have to put a LED on motor terminals and then when stops running motor so I can tell if power is getting thru switch to motor cause just because y'all hear switch snap does not hateful switch has closed. Is a magnetic reed switch a lifetime type of switch or tin can contacts get bad?

Is a magnetic reed switch a lifetime type of switch or tin contacts become bad?

They are pretty adept as to lifetime, but a motor load is rather nasty. If the clock still reliably works on that single "C" prison cell the switch is OK.

If you practise run into switch life problems, attempt this: Wire a 0.1 uF capacitor in series with a 100 Ohm resistor so wire the combination across the switch contacts. For this use, any inexpensive capacitor, like a disc ceramic, will exercise and the resistor can be quite depression ability, ¼ Watt and ½ Watt are the almost available.

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I know this is a different topic, just since y'all brought it up, that's a very surprising matter to say. Didn't you lot pay for the solar system? A lot? More often than not solar systems are very expensive so maximizing efficiency, every bit @berkeman said, is typically disquisitional to the economical success of the organization. Nosotros'd be delighted to help notice ways to maximize the economics of your organization if you want.

Have 465 watt solar panels
Take 300 watt inverter
Have 26 car batteries
Accept spent $500

Have 465 watt solar panels
Have 300 watt inverter
Have 26 automobile batteries
Accept spent $500

Ok! A quick calc tells me that depending on where you lot alive you lot might get the coin back in iii-6 years (if you don't waste it). That's quite good.

might get the money back in 3-6 years

Very much depending on Breadth and average Cloud Comprehend. My 40W (Nominal) Console, spends most of its daylight fourth dimension delivering around 6W or so.

Using a footstep down transformer 12 V tin be cut downwards to 1.5 Five. In a step downward transformer number of turns in secondary windings is less than the number of turns in primary windings.

Ok! A quick calc tells me that depending on where y'all live you might get the money dorsum in 3-half dozen years (if you don't waste information technology). That's quite expert.

Just in fourth dimension to supercede those 26 automobile batteries! :)

Off grid is expensive, and has ongoing costs. If there is no alternative, OK. Only as a means to relieve money? probably not.

Using a stride downwards transformer 12 V can be cutting down to 1.five V. In a step down transformer number of turns in secondary windings is less than the number of turns in primary windings.

That only works for AC. The OP seems to be asking mainly about DC ability. That's why we have suggested a DC-DC "Buck" converter.

You did not specify max electric current, so I took a estimate: https://www.maximintegrated.com/en/products/power/nanopower-dc-dc-regulators/MAX77596.html

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12v To 1.5 V Resistor,

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