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Help with Diode

aHumanError

May 7, 2017
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May 7, 2017
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Good evening.

I'm currently undertaking a project on my car fitting a reverse camera. My knowledge of electronics is basic at best, and the instructions calls for a "12v diode 2w or up rating". Problem is that I don't know what type of diode I need (Zener, Schottky, etc). Most of the ones I find are rated for much higher voltages and high amps.

Can anybody recommend the right diode to use?
 

Martaine2005

May 12, 2015
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A standard 1N4xxx series will be fine.
Voltage and amp ratings are maximum values. So don’t worry about that. A 1N4007 is rated for a maximum of 1000V and 1A.

Martin
 

AnalogKid

Jun 10, 2015
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Where is the diode connected? It is important. In your context, "diode" is way too ambiguous. 2 W sounds like a zener spec rather than a rectifier spec, but for a zener there needs to be a resistor in series with it. 2 W in a rectifier would be over 2 A of current, way too much for your device.

Link to the product you are installing? PDF of the instruction sheet? Anything?

ak
 

aHumanError

May 7, 2017
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May 7, 2017
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Thanks for the responses.

So I'm wiring this camera into the android system in my car, and because it's an aftermarket system it doesn't know when I select reverse or not (in order to open the reverse camera app) but the system comes with a wire harness that allows for this. I have to wire the reverse positive to a "detection" wire, and the instructions tells me to use this diode between the detection wire and the 12v supply.

I have no clue why it didn't come with the rest of it since it will probably cost about 5p. I know what diodes are, but I don't know about the different types etc..

Here's the instructions: https://cdn.shopify.com/s/files/1/1...p_cam_wiring_for_RSNAV_S2_Android_Systems.pdf
 

HellasTechn

Apr 14, 2013
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That's quite strange. What is a diode connected like that needed for ? To block current from flowing from the camera to the reverse light ?

2 W in a rectifier would be over 2 A of current, way too much for your device
Not really.
2 Watts under 12V (car battery voltage) requires a diode with forward bias current capability of roughly 170mA. (I = P/V)
So an 1N4007 Should be just fine.

2 W sounds like a zener spec rather than a rectifier spec,
Generally speaking yes but If it was asking for a zener, the zener voltage would be mentioned also not just the wattage.
 
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aHumanError

May 7, 2017
5
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May 7, 2017
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That's quite strange. What is a diode connected like that needed for ? To block current from flowing from the camera to the reverse light ?

I'm not sure what the purpose of it is, I just follow the instructions.

It's from the same company who supplied the system which came with it's own wiring loom to integrate into the car. So I'd assume it has some kind of purpose.
 
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