Consumer Electronics

Electronics Repair Questions? Ask an Electronics Technician

Ask an Expert,
Get an Answer ASAP!

This answer was rated:

How can i convert 5v easily to 12v with some available parts…

How can i convert 5v...
How can i convert 5v easily to 12v with some available parts its for a small project for automotive use , parts store not open today , i need to convert 5v to power a 12v relay , i have a lot of old stuff i can scavange parts from , dvd players , usb , etc
Show More
Show Less
Ask Your Own Consumer Electronics Question
Answered in 2 hours by:
10/15/2017
Louie
Louie, Technician
Category: Consumer Electronics
Satisfied Customers: 13,212
Experience: 25+ yrs. experience in the field and 5+ yrs. online, down to component level.
Verified

Hi and welcome to JustAnswer, I’m Louie. Sorry you had to wait awhile but I’ll do my best to help.
Initially, re-confirm and post back that this is a"...project for automotive use..." hence 12V is available somewhere.
And to "...convert 5v to power a 12v relay...", the relay coil specs would be needed particularly how much current it draws to latch.

Have you considered a switching transistor enabled by 5V? ...but the relay would still be powered by 12V?

This is an independent site and members of this online community provide information, repair tips, technical assistance as a form of paid Q & A service.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
Hello Louie , thanks for assisting me , as i mentioned before i will need to trigger a 12V Relay comming from a 5V sensor output
Customer reply replied 6 months ago
It is a 5V output from a Ac Pressure sensor witch doesnt draw so much current

Your first approach appears to be "...convert 5v easily to 12v..." since:

  • 12V Relay; and
  • trigger...from a 5V sensor output.

And the prescribed solution is to build a DC-to-DC converter; i.e. 5V + switching regulator = 12V

However, there is an easier approach; i.e.:

  • 5V output from a Ac Pressure sensor;
  • triggers a switching transistor;
  • that turns on the 12V powered relay.
Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
But as you mentioned will the transistor help me based on my drawing , will it replace the 5Volt Relay in a kind of a way with a minimum current to trigger the 12 Volt Relay

Yes.

Consider/try:

  • diode cathode/pin 86 to a +12V supply;
  • diode anode/pin 85 to the collector of an NPN switching transistor such as a DTC143ES;
  • emitter of this switching transistor to ground;
  • base of this switching transistor to the pressure switch output.

A moment while I prep a schematic.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
Considering that i dont have the 5 volt relay , and using the transistor directly conected to the 5 volt to power the 12 volt relay

A 5V relay is not needed.

Perhaps it would be better to look at it this way:

  • 5V output of pressure switch needed only to turn on (not power) the switching transistor;
  • transistor's collector and emitter pins to serve as electronic switch;
  • transistor's collector and emitter pins switches relay pin 85 to ground;
  • relay energized;
  • relay contact supplies +12V to load/compressor.

Please click HERE.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
Ok ... Louie just some questions an bear a little patience with me as im no electrical expert... So basically what you send me or explained is the 5Volt from the pressure switch goes through the Transistor? To activate the relay?What does a transisctor literally do?
Will it provide a minimum pulse for the relay?
Any drawbacks usimg transisctors heating?
What type of transisctor am i looking for?
In what type of devices can i scavange for a transisctor?

I understand.

On:

  • 5Volt from the pressure switch goes through the Transistor? - negative; the 5V just turns on the switching transistor and is not passed/feed through;
  • What does a transisctor literally do? - Think of it as an electronic (relay) switch where the 5V is only needed to turn it on;
  • Will it provide a minimum pulse for the relay? - yes as the transistor's collector/emitter acts just like a switch. It does not matter whether you have 5 or 12 volts as it only works on or off;
  • Any drawbacks usimg transisctors heating? - none;
  • What type of transisctor am i looking for? - as posted above "...an NPN switching transistor such as a DTC143ES...";
  • In what type of devices can i scavange for a transisctor? - most electronic devices / circuit boards would have an NPN (switching) transistor.
Ask Your Own Consumer Electronics Question

Please click HERE.

As shown:

  • the leftmost leg (1) would be the emitter that must be connected to the system ground;
  • middle leg would be the collector (2) and referring to my earlier diagram would go to pin 85 of the 12V relay;
  • while the right leg (3) would be the base and to be connected to "5Volt from the pressure switch".

See the video tutorial HERE for insight to determine/verify base, collector and emitter.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
Ok thank you very much , i will try it out , and get in contact with you again to let you know how it worked out

Yes please; an update when able.

A friendly reminder; there are several versions of the leg arrangements of NPN transistors depending on the suffix of the transistor's Part Number.

Also you may want to carefully use alligator clips with wires when experimenting connections. Please click HERE.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
Hello Louie i happened to find a NTE2367 they said its the equivelent of the DTC143ES , is this allright?

Yes, an NTE2367 would work equally just like the DTC143ES.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
Hello Louie i am a little off the tracks or confused
Customer reply replied 6 months ago
With the transistor do i have to make any changes in my drawing , first time experimenting with a transistor ,,

Please click HERE.

And if you haven’t done so, please provide a positive rating (3 to 5 stars) at the top of your page.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
I dont plan in using the Diode anymore in the relay , so will it still be necesary to hook 86 and 30 together ? , whats your opinion ? For me skipping the diode?

The circuit would still work even without the diode.

However, the diode protects the relay coil and in this instance, more importantly also the transistor.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
Time to test evryhting is hooked , ...

Ideally, test / monitor with three (3) volt/multi-meters:

  • base of transistor;
  • collector of transistor; and
  • 87 of relay.

Or test each point one-at a-time.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
In the last diagram you send i saw that you hooked 86 to 30. Why is that

86 is the power feed to the relay coil.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
im still missing something i cannot get 12v to the compressor , but i can hear the relay Buzz , any idea if i misonnected the pins of the transistor wrong?

Please post back with clear pictures of the "...pins of the transistor..." Click HERE.

These pictures would then serve as common references.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
ok Louie sorry to take to much of your time , i will make a drawing of what i have done , from scratch

Can you post pictures of the actual transistor, connections and relay?

These would allow me to see what you are seeing.

Ask Your Own Consumer Electronics Question

If 86 is connected to the collector of the transistor, then:

  • 85 should go to '12V battery' or even 30;
  • emitter of transistor should go to ground; and
  • base of transistor should go to 'pressure switch'.
Ask Your Own Consumer Electronics Question

These / above would be the correct connections to the transistor.

To test, momentarily short the red and black. The relay should click/engage.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
The relay just buzzes but no power to the other side

Sorry. but please complete the description:

  • relay just buzzes - when ?????;
  • no power to the other side - of what / which pin(s)?
Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
At 87 there is no power
Customer reply replied 6 months ago
When ac switch is on relay buzzes , then at 87 there is no power coming out to the compressor

I understand, "...ac switch is on relay buzzes , then at 87 there is no power coming out to the compressor..."

What are the voltages at:

  • pin 30;
  • pin 86;
  • pin 85;
  • collector of transistor; and
  • at the base?

Did you try (momentarily) shorting the black and red aliigator clips?

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
Pin 30=12volt
Pin86= 11.56
Pin85= is hooked to pin 30 so the same voltage
Collector= voktage variation
Base= 3 volts

Did you try (momentarily) shorting the black and red aliigator clips?

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
No havent tried that

Please try and determine if relay would engage = 12V to compressor.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
You mean take the aligator that feeds the 86 , or the ground from the transistor to the 86?

Yes; please short together the red and black alligator clips.

Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
sir , when i short them the relay actuates normally , whit no power on the ignition

Based on this, then the "...Base= 3 volts..." is not enough to trigger the transistor; was expecting 5V.

This is very significant as with only 3V available from the 'pressure switch', then even a 5V relay may likely not work too.

Two potential workarounds:

  • raise the 3V to 5V (least likely doable); or
  • make the transistor more sensitive (more likely - replace).
Ask Your Own Consumer Electronics Question
Customer reply replied 6 months ago
What type of transistor am i looking for ??

A Darlington pair; i.e. two (2) transistors in 1 package such as a TIP122 or a 2N6387.

Louie
Louie, Technician
Category: Consumer Electronics
Satisfied Customers: 13,212
Experience: 25+ yrs. experience in the field and 5+ yrs. online, down to component level.
Verified
Louie and 87 other Consumer Electronics Specialists are ready to help you
Ask your own question now
Customer reply replied 6 months ago
Thank you very much Louie , looking forward to work with you again
Was this answer helpful?
Ask Louie Your Own Question
Louie
Louie
Louie, Technician
Category: Consumer Electronics
Satisfied Customers: 13,212
13,212 Satisfied Customers
Experience: 25+ yrs. experience in the field and 5+ yrs. online, down to component level.

Louie is online now

A new question is answered every 9 seconds

How JustAnswer works:

  • Ask an ExpertExperts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional AnswerVia email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction GuaranteeRate the answer you receive.

JustAnswer in the News:

Ask-a-doc Web sites: If you've got a quick question, you can try to get an answer from sites that say they have various specialists on hand to give quick answers... Justanswer.com.
JustAnswer.com...has seen a spike since October in legal questions from readers about layoffs, unemployment and severance.
Web sites like justanswer.com/legal
...leave nothing to chance.
Traffic on JustAnswer rose 14 percent...and had nearly 400,000 page views in 30 days...inquiries related to stress, high blood pressure, drinking and heart pain jumped 33 percent.
Tory Johnson, GMA Workplace Contributor, discusses work-from-home jobs, such as JustAnswer in which verified Experts answer people’s questions.
I will tell you that...the things you have to go through to be an Expert are quite rigorous.

What Customers are Saying:

I'm screaming your praises!! WOW! I plugged my TV in and bammo! The picture came on bright and beautiful. What a relief! YOU saved me some money and headache.

VMUnited States

I love this site! $9 instead of a repairman or new/used frig can't be beaten. This older woman will worry less now that she knows about this site. Bless you all.

WindyUSA

Wonderful service, prompt, efficient, and accurate. Couldn't have asked for more. I cannot thank you enough for your help.

Mary C.Freshfield, Liverpool, UK

This expert is wonderful. They truly know what they are talking about, and they actually care about you. They really helped put my nerves at ease. Thank you so much!!!!

AlexLos Angeles, CA

Thank you for all your help. It is nice to know that this service is here for people like myself, who need answers fast and are not sure who to consult.

GPHesperia, CA

I couldn't be more satisfied! This is the site I will always come to when I need a second opinion.

JustinKernersville, NC

Just let me say that this encounter has been entirely professional and most helpful. I liked that I could ask additional questions and get answered in a very short turn around.

EstherWoodstock, NY

< Previous | Next >

Meet the Experts:

John

John

Engineer and electronic enthusiast for more than 12 years.

227 satisfied customers

I am here to help you!

Steve G.

Steve G.

Engineer

2,358 satisfied customers

VP of electronic repair company. Audio nut since 1974. Home Theater advisor. Vinyl holdout!

Louie

Louie

Technician

13,212 satisfied customers

25+ yrs. experience in the field and 5+ yrs. online, down to component level.

Russell H.

Russell H.

Service Tech

4,358 satisfied customers

8+ years of professional experience

Rod

Rod

Systems Engineer

1,319 satisfied customers

FCC Commercial Licenses, BSCS, ASEET, 40+years Electronics & Communication Systems

Greg A.

Greg A.

Engineer

1,281 satisfied customers

Engineer / Consultant

Martin

Martin

Engineer

1,244 satisfied customers

16 years, include works in aluminium plant, industrial machinery, military weapons, programming

< Previous | Next >

Related Consumer Electronics Questions
Looking for panasonic pnlc1040 batterry charger. I would
looking for panasonic pnlc1040 batterry charger JA: How long have you had your PNLC1040? Customer: I would guess 10 years JA: What have you tried so far with your Panasonic product? Customer: I tried … read more
Richard Hill
Richard Hill
Director
Vocational, Technical or Trade Scho
56 satisfied customers
Trying to pair the Bluetooth to my headset. The phone is a
the phone is a KX-TG9541, the headset is Plantronics Savi W740 … read more
p0llinate
p0llinate
Bachelors of Science
14 satisfied customers
Have lost my instruction book on how to record the answe.
have lost my instruction book on how to record the answe … read more
Richard Hill
Richard Hill
Director
Vocational, Technical or Trade Scho
56 satisfied customers
MY standby light continuwa to blink on my Sony Trinitron TV
MY standby light continuwa to blink on my Sony Trinitron TV ans I am unable to get a picture, … read more
Jack
Jack
technician
factory trained engineer
2,161 satisfied customers
I have an older Sony Handycam Digital Video Camera Recorder.
I have an older Sony Handycam Digital Video Camera Recorder. On operating guide it shows multiple model numbers re; operation so I do not know exactly the correct number to re; here are the numbers; P… read more
Russell H.
Russell H.
Service Tech
Vocational, Technical or Trade Scho
4,358 satisfied customers
My computer wouldn't come on for a couple of hours when I
My computer wouldn't come on for a couple of hours when I turned it on. … read more
Richard
Richard
IT Manager
IT Manager, Consultant
3,395 satisfied customers
I want to transfer my I phone contacts phone # to my new
I want to transfer my I phone contacts phone # to my new KX-TGF572 with Link2cell cordless phone. … read more
Richard Hill
Richard Hill
Director
Vocational, Technical or Trade Scho
56 satisfied customers
Unable to tune without static on wireless headset.
Unable to tune without static on wireless headset. … read more
Richard
Richard
IT Manager
IT Manager, Consultant
3,395 satisfied customers
I have a LG Ultra Wide monitor that is no connecting to my
I have a LG Ultra Wide monitor that is no connecting to my pc. Also I cannot get the memu to work on the monitor. The only direction it will go in is to turn the monitor off. … read more
Jack
Jack
technician
factory trained engineer
2,161 satisfied customers
The outdoor temp does not display on the indoor momitor.
the outdoor temp does not display on the indoor momitor … read more
Harry
Harry
1,395 satisfied customers
I have three ViewSonic PJD5134 Projectors and they are not
I have three ViewSonic PJD5134 Projectors and they are not receiving signal from the HDMI... … read more
Harry
Harry
1,395 satisfied customers
How can I unblock a blocked number. Panasonic. Page 47 in
How can I unblock a blocked number JA: What's the brand and model of your product? Customer: Panasonic JA: What have you tried so far with your Panasonic product? Customer: Page 47 in manual, dressing… read more
p0llinate
p0llinate
Bachelors of Science
14 satisfied customers
We have two UB5338C whiteboards which we need to source the
Hi Pearl, we have two UB5338C whiteboards which we need to source the brackets for, as these boards have been relocated and in the move the brackets are no longer available. can you advice how we can … read more
Russell H.
Russell H.
Service Tech
Vocational, Technical or Trade Scho
4,358 satisfied customers
WE have a Panasonic 5.8 GHZ mobile telephone been given to
WE have a Panasonic 5.8 GHZ mobile telephone been given to us. … read more
Greg A.
Greg A.
Engineer
Bachelor's Degree
1,281 satisfied customers
I reset both of my paper whites readers and now I can get
Hi Pearl. I reset both of my paper whites readers and now I can get them working again...please HELP … read more
info tech
info tech
Self Employed
Vocational, Technical or Trade Scho
341 satisfied customers
Local handyman trying to determine why smoke alarm is
local handyman trying to determine why smoke alarm is chirping … read more
Aric
Aric
Owner/Operator of a custom AV company
Run A/V and repair business for over
13,663 satisfied customers
I followed all the instructions but have not dial tone.
I followed all the instructions but have not dial tone … read more
Richard
Richard
IT Manager
IT Manager, Consultant
3,395 satisfied customers
I have a problem opening youtube. Sony tv. Let me check.
it has been five days and it was work until one morning we got trying to access youtube but i count open up … read more
Shahid
Shahid
Owner of Repair Shop
High School or GED
3,505 satisfied customers
Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Disclaimer: Information in questions, answers, and other posts on this site ("Posts") comes from individual users, not JustAnswer; JustAnswer is not responsible for Posts. Posts are for general information, are not intended to substitute for informed professional advice (medical, legal, veterinary, financial, etc.), or to establish a professional-client relationship. The site and services are provided "as is" with no warranty or representations by JustAnswer regarding the qualifications of Experts. To see what credentials have been verified by a third-party service, please click on the "Verified" symbol in some Experts' profiles. JustAnswer is not intended or designed for EMERGENCY questions which should be directed immediately by telephone or in-person to qualified professionals.

Show MoreShow Less

Ask Your Question

x