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negative to positive inverter

Printed From: the12volt.com
Forum Name: Car Security and Convenience
Forum Discription: Car Alarms, Keyless Entries, Remote Starters, Immobilizer Bypasses, Sensors, Door Locks, Window Modules, Heated Mirrors, Heated Seats, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=126185
Printed Date: June 13, 2021 at 1:00 PM


Topic: negative to positive inverter

Posted By: phil6710
Subject: negative to positive inverter
Date Posted: February 16, 2011 at 10:15 PM

I would like to make my own door lock - to + inverter. For installs on keyless entry units on vehicals like GM and some Dodges. I have taken the inverter modules apart and they seem pretty simple. But I would like to know what parts I would need and how to wire it up. Thaks.

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Solartech Window Tinting and Electronics,contract installer



Replies:

Posted By: KarTuneMan
Date Posted: February 16, 2011 at 10:33 PM
A relay..... ?

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Posted By: Ween
Date Posted: February 16, 2011 at 10:51 PM
i'm guessing he's referring to the ones with the transistors in them. googling 'transistor circuits' should give a few choices with tutorials.
mark




Posted By: phil6710
Date Posted: February 17, 2011 at 12:50 AM
Yes I know I could use 2 relays but I would like to it with transistors and I think a rectifier dioed.

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Solartech Window Tinting and Electronics,contract installer




Posted By: howie ll
Date Posted: February 17, 2011 at 6:10 AM
Done both, relays tend to be more reliable, but either Oldspark or Mr. Idiot can help with the circuitry, PNP power transistor + 47Kohm resistor + a diode.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: Mike M2
Date Posted: February 17, 2011 at 6:25 AM
I can't see the point. A DEI 451M is designed to do this exact same thing...

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Mike M2
Tech Manager
CS Dealer Services




Posted By: howie ll
Date Posted: February 17, 2011 at 7:46 AM
If it's a cost factor I go to Radio Spares (= Farnel or Mouser in the US) I buy "mini" or PCB relays, diode them, wire them up as DEI 8616 and the cost is about 1/3 the DEI product less my time though I make up about 10 at a time.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: KPierson
Date Posted: February 17, 2011 at 9:04 AM
I would run a 470 ohm resistor in to the base of a PNP transistor (like a 2n3906). The other end of the 470 ohm resistor would be your (-) input.

I would connect the emitter to 12vdc

I would connect the collector to a 22 ohm resistor. The other end of the 22 ohm resistor is your (+) output.

I would connect a diode between the (+) output and ground.

The 470 ohm resistor provides your base current. The 22 ohm resistor protects the output from excessive current that can damage the transistor. The diode protects the transistor from reverse voltage spikes caused by the collapsing of magnetic fields most commonly found in relays.

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Kevin Pierson




Posted By: KarTuneMan
Date Posted: February 17, 2011 at 10:49 AM

KPierson wrote:

I would run a 470 ohm resistor in to the base of a PNP transistor (like a 2n3906). The other end of the 470 ohm resistor would be your (-) input.

I would connect the emitter to 12vdc

I would connect the collector to a 22 ohm resistor. The other end of the 22 ohm resistor is your (+) output.

I would connect a diode between the (+) output and ground.

The 470 ohm resistor provides your base current. The 22 ohm resistor protects the output from excessive current that can damage the transistor. The diode protects the transistor from reverse voltage spikes caused by the collapsing of magnetic fields most commonly found in relays.

contract installer..... what is your time worth?



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Posted By: Ween
Date Posted: February 17, 2011 at 1:51 PM
but the transistor is elegant, and the relay, brute force.  learning can be fun for the one who tries. 




Posted By: howie ll
Date Posted: February 17, 2011 at 2:02 PM
Sorry kids I'm with Uncle Gary here Mr. Ween, I get the impression you do a lot of BlueTooth kits. For adaptors for exotica from 2000 on which kept changing their plugs and layout, e.g. BMW and Mercedes, look at Kram in Denmark, they actually manufacture a lot of head unit plugs as OEM for European manufacturers.

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Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.




Posted By: Ween
Date Posted: February 17, 2011 at 2:54 PM
no, just a little bored today, caught me in a good mood.




Posted By: oldspark
Date Posted: February 17, 2011 at 4:16 PM
Mike M2 wrote:

I can't see the point. A DEI 451M is designed to do this exact same thing...

I generally think the opposite - why use a relay when a simple transistor will do....

Small, quiet, reliable.
No clicking, no BIG caps and resistor needed for delays....


All you need is a typical "Open Collector" output.
A +ve voltage via a resistor to the Base of an NPN transistor.
The Emitter is connected to GND (0V).
The Collector is its output - it connects to ground when the Base voltage exceeds ~0.7V.
(There's a bit more, but KIS for now.)




Posted By: phil6710
Date Posted: February 17, 2011 at 11:14 PM
KarTuneMan wrote:

KPierson wrote:

I would run a 470 ohm resistor in to the base of a PNP transistor (like a 2n3906). The other end of the 470 ohm resistor would be your (-) input.

I would connect the emitter to 12vdc

I would connect the collector to a 22 ohm resistor. The other end of the 22 ohm resistor is your (+) output.

I would connect a diode between the (+) output and ground.

The 470 ohm resistor provides your base current. The 22 ohm resistor protects the output from excessive current that can damage the transistor. The diode protects the transistor from reverse voltage spikes caused by the collapsing of magnetic fields most commonly found in relays.

contract installer..... what is your time worth?


  My time is worth about $100 per hour. I am sure time wise it would not be cost effective. But It would be someting to do in the off season and possibly I might learn some thing too. I perfer to make my own transponder bypasses vrs useing a transponder box. So maby knowing how to make my own inverter with some cheap radio shack parts could be usefull in a pinch. If maybe I run out of relays or inverters. I would think it would take just as long to wire up2 relays as it would to solder up a inverter.

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Solartech Window Tinting and Electronics,contract installer




Posted By: howie ll
Date Posted: February 18, 2011 at 12:53 AM
And here endeth this post. Everyone is right; no-one is wrong, keep to your views, try the other's philosophy if it works.

-------------
Amateurs assume, don't test and have problems; pros test first. I am not a free install service.
Read the installation manual, do a search here or online for your vehicle wiring before posting.





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