Consumer Electronics

Electronics Repair Questions? Ask an Electronics Technician

Ask an Expert,
Get an Answer ASAP!

Consumer Electronics
This answer was rated:

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

its for a small project...
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: 12,784
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 1 month 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 1 month 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 1 month 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 1 month 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 1 month 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 1 month 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 1 month 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 1 month ago
Hello Louie i am a little off the tracks or confused
Customer reply replied 1 month 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 1 month 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 1 month 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 1 month 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 1 month 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 1 month 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 1 month 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 1 month ago
At 87 there is no power
Customer reply replied 1 month 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 1 month 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 1 month 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 1 month 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 1 month 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 1 month 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: 12,784
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 29 days ago
Thank you very much Louie , looking forward to work with you again
Ask Louie Your Own Question
Louie
Louie
Louie, Technician
Category: Consumer Electronics
Satisfied Customers: 12,784
12,784 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

12,784 satisfied customers

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

Russell H.

Russell H.

Service Tech

4,171 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

Martin

Martin

Engineer

1,242 satisfied customers

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

Greg A.

Greg A.

Engineer

1,213 satisfied customers

Engineer / Consultant

< Previous | Next >

Related Consumer Electronics Questions
My 20 year old 5 CD changer just quit while playing and I am
My 20 year old 5 CD changer just quit while playing and I am unable to use the Open/close function to get the CD's out … read more
Louie
Louie
Technician
12,784 satisfied customers
I had to change the batteries in my safe today and now I can
I had to change the batteries in my safe today and now I can not get the combination control back in place. Also the green and white wires came loose. … read more
Aric
Aric
Owner/Operator of a custom AV company
Run A/V and repair business for over
13,650 satisfied customers
I got disconnected and was asking about a Panasonic
I got disconnected and was asking about a Panasonic KX-TGE433B time issue. … read more
p0llinate
p0llinate
Bachelors of Science
14 satisfied customers
I have a jvc cd radio in my truck. a year ago i discovered
i have a jvc cd radio in my truck. a year ago i discovered it can display the song title/artist being played through bluetooth from my samsung... at least up until last night now it displays the first… read more
Pete
Pete
Engineer
Bachelor\u0027s Degree
1,109 satisfied customers
I have a sony cd 300 changer disc cdp cx355 need repair.
I have a sony cd 300 changer disc cdp cx355 need repair. Where can I send it. … read more
Electrotech2017
Electrotech2017
Audio and Video Technician
Vocational, Technical or Trade School
81 satisfied customers
I have a Garmin GPS that's not working. After the initial
I have a Garmin GPS that's not working. After the initial screen, all I get is a white screen, with a car.… read more
Russell H.
Russell H.
Service Tech
Vocational, Technical or Trade Scho
4,171 satisfied customers
The answering phone was working just fine. After I increased
The answering phone was working just fine. After I increased the number os rings from 4 to 6, the phone no longer works correctly. Instead wen an incoming caller calls, the machine answers, plays my r… read more
p0llinate
p0llinate
Bachelors of Science
14 satisfied customers
I have a Magnavox Disc Recorder &Video Cassette Recorder.
I have a Magnavox Disc Recorder &Video Cassette Recorder. Something is wrong. I can play a DVD but I can not get a VHS Tape to play. Every time I put a tape in it cuts off.. I get this info on my TV.S… read more
Pete
Pete
Engineer
Bachelor\u0027s Degree
1,109 satisfied customers
I have a EverFocus DVR and I need a manual how could I get
I have a EverFocus DVR and I need a manual how could I get one? It's a ECOR DVR … read more
GeekGal
GeekGal
IT Director
Bachelors Degree
422 satisfied customers
No dialtone on any of the 4 handsets. Model KXTF340. shows
no dialtone on any of the 4 handsets. Model KXTF340. shows "in use … read more
p0llinate
p0llinate
Bachelors of Science
14 satisfied customers
As I have recently moved I've (temporarily??) lost the
Hi, as I have recently moved I've (temporarily??) lost the manual for my Panasonic DMR-BWT 760 which I haven't yet used. … read more
Electrotech2017
Electrotech2017
Audio and Video Technician
Vocational, Technical or Trade School
81 satisfied customers
Will installation of a subwoofer and amp be detrimental to.
Will installation of a subwoofer and amp be detrimental to … read more
Aric
Aric
Owner/Operator of a custom AV company
Run A/V and repair business for over
13,650 satisfied customers
I have a sentry safe the safe is open but I don't have the
I have a sentry safe the safe is open but I don't have the combo is there any way for it to be reset? … read more
p0llinate
p0llinate
Bachelors of Science
14 satisfied customers
My BOSE radio/cd player plays some cd's and not others. Cd's
My BOSE radio/cd player plays some cd's and not others. Cd's are in good condition and there appears to be no rationale to this. … read more
Richard
Richard
IT Manager
IT Manager, Consultant
3,207 satisfied customers
The telephone (Dect 6.0) indicated limited battery life so I
The telephone (Dect 6.0) indicated limited battery life so I replaced the two batteries with two flashlight batteries. Now it asks to use rechargeable batteries. Did I make a mistake? … read more
p0llinate
p0llinate
Bachelors of Science
14 satisfied customers
I have a Sony digital Photo Printer UP-CR10L I just ran
I have a Sony digital Photo Printer UP-CR10L I just ran updated now everything is in Chinese? How do I get it back to English … read more
Russell H.
Russell H.
Service Tech
Vocational, Technical or Trade Scho
4,171 satisfied customers
Nikon D3200 will not read the sim card, or any card. Im
Nikon D3200 will not read the sim card, or any card. Im removed the battery, and put it back as a reset try, but no luck. How can this be diagnosed? … read more
Russell H.
Russell H.
Service Tech
Vocational, Technical or Trade Scho
4,171 satisfied customers
About 15 years ago I purchased 20 embroidery designs for my
About 15 years ago I purchased 20 embroidery designs for my Janome 9000 through our Janome Store. The store personnel downloaded the designs from the OESD site. I have used 17 of them and have .sew fi… read more
Pete
Pete
Engineer
Bachelor\u0027s Degree
1,109 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