How do I determine what diode or "rating" I would need? Someone told me already but I forgot which one to use when I went to Radio Shack and I can't find the thread anymore.

For example:
Which diode should I use to stop current to my reverse lights when I flick a switch to activate my rearview camera while going forward?

IN4001?
IN4003?
IN4004?

Thanks.

 

Your best bet would be to cut the reverse wire and put an amp meter inline with it. Put the car in reverse and measure the current draw. Once you know the 'on' current draw double that value and that would be the rating of diode you would want to use.

 

You don't need to do this. If you hook it up right the current that supplies the reverse light will not go through the diode. When hooked up correctly there will be only a small amount of current through this diode, and just about any diode will do. You can just get the one with the highest current rating, and you will have way more than you need.

 

Thanks.

 

Shunra is correct, you actually don't need a diode in the line with your reverse light, you need it inline with your video switcher. The input on the video switcher is most likely extremely low current (less then 10mA) so the diode you use won't matter.

Sorry to mislead you! However, if you ever wanted to put a diode inline with your reverse lights follow what I posted above!

 

Or if you know the bulb wattage you could reverse calculate the current to save cutting the wires.

 

My RCA cable of the camera is hooked up to my AVIC-D1.

My camera has one + (red) and one - (black) so I grounded the black to the body and t-tapped the red into the reverse light wire. So the reverse lights actually power the camera when I hit reverse.

I want to use a switch to give direct power to the camera and the diode will block power to the reverse lights. When the switch is off, the diode will allow power to the camera. That is what I am trying to accomplish. So the Diode will go between the camera power line and the reverse lights.

Could I just try a 1N4004 or is that too weak?

 

I think we discussed this a while back in another thread.

Anyways, I remember telling you to use a 1N4001 diode with the cathode connected to the camera (striped side) and the anode to your reverse lights. This will allow you to turn on the camera without turning on the reverse lights.

BTW the 1N4001 to 1N4007 diodes are rated from 50V to 1000V peak repetitive reverse voltage. This means that the diode will breakdown and conduct reverse current when you exceed the said voltage.

In terms of performance, the 1N400X series has ~1V forward voltage drop @1A. The reverse current is about 5uA at the rated Vr (reverse voltage). This should not be enough to turn on your reverse lights.

Anyways the 1N4004 is rated for 400V compared to 50V for the 1N4001 so you should be fine.

 

Yes! I couldn't find the thread where we discussed this and I couldn't remember your SN so I couldn't PM you. I used the 1N4004 and it seems to be work. I just have to hook the switch up today and I should be good to go...

Thanks for finding this thread, now I remember what we had previously discussed.

 

And now I know what I can use one of the two unused buttons on my ashtray insert for! hah! manual rear camera turnon! woot woot. One more button to go.

 

^^^ I was thinking the same thing....

1. System shutdown.
2. V1 power
3. Reverse Camera


What else?

 

1. Shutdown override for carPC- keeps PC up when car turns off
2. Manual carPC startup&shutdown- turns on/off carPC even if the car is off
3. Screen kill- immediately kills power to xenarc screen- when cops come a'knockin'
4. Valet/Alarm override (might move to lower glovebox)- carPC doesn't turn on if switch is depressed or alarm is going off.
5. Rear Camera manual powerup
6. Unknown