T&L Publications

For the lights grounded to the bar, I would use a brass split washer or galvanized star washer between the lamp and bar. Then once good contact were made, some plain old rustolium spray paint to cover up the metal and keep it from rusting. Any specific reason for brass? There's already grade-8 spli...

An RTV compound (also called caulk or silicone rubber) would be ideal. It will flex with your truck's chassis and remain watertight. The exterior versions are also UV resistant. It does not conduct electricity. Try the local Home Despot or similar stores. Home Despot - ha ha! Was that really a typo...

I need some sort of grease/paste/putty/sealant to seal up the bare metal that is grounding my rollbar lights on my pickup. I have good grounds for all of my lights, and I want it to stay that way. As it is right now, if I were to drive it in the rain I'm sure I'd start seeing orange rust streaks run...

Robert Reed wrote:The one good feature about that method is that it sell more yards of wire for the manufacturer. :grin:

That's about what I figured. You have to wonder how these rumors get started...

I heard a rumor that if you buy considerably longer spark plug wires for a car, then wrap them into a coil shape somehow that you can get better gas mileage/more power (just like the fancy spark plugs are supposed to do, I guess). What, if any, circumstances would starve a spark plug, and could also...

Actually, the faster switch time i was referring to was not in the switch itself, but the relay contacts. I understood that. When the voltage is allowed to go higher across the coil (resistor,zener, whatever) the relay contacts can open faster which means less wear. Not sure how much wear is saved ...

dyarker wrote:With a 3A rated switch (I think you said), and 133mA coil current, your switch is safe with just the diode.

It's rated 3A at 125VAC, but as Bigglez told me in a different discussion AC rated switches are not as hefty as DC switches for the same voltages and amperage.

Faster opening contacts sometimes reduces wear caused by pitting or even partial welding of the contacts simply because the contacts can move away from each other at a faster rate which reduces arc time. The way to acheive this faster turn off time is to allow the coil voltage to go higher, but not...

Replace the MOSFET with a switch that has no capacitance and the true theory of the relay coil will become more apparent. Not to draw a topic beyond its usefullness, but I am using a switch. If I had MOSFETs in mind then I probably would not need a relay at all, right? Analyzing a MOSFET's effect m...

That is why I recommended 1N400x for use in a vehicle. Especially because they probably won't be mounted on a PCB, but point to point on the relay terminals. Right? Actually, because it's already been constructed and crammed under the dash, they'll probably be point to point between wires going to ...

For that relay, in a vehicle, a 1N4001 (1A, 50V PIV) should work fine. As will 1N4002 (1A, 100V PIV) or 1N4003(1A, 200V PIV). If using solid state relay driver, a faster diode would be better. Like 1N4148 for coil currents 150mA or less. A 1N4148 would work electrically for this project too, but is...

The diode must dissipate the energy in the coil as heat. So a power diode (aka a rectifier) is needed. If the relay is small (limited energy storage) a signal diode will suffice. The relay coil draws 133 ma, has a resistance of 90 ohms, and is run with 14.4V. I have no idea as to what a regular Rad...

Greetings Zach, is there any reason not to use LEDs as diodes LEDs are fragile, and can't be used in place of a power diode. The reverse voltage rating of most LEDs is 5V, in this application almost the full battery voltage (10 - 16V) would appear across the LED when the coil was energized. You mea...

A series resistor to lower coil voltage is not necessary and in fact will lower the overall reliability by adding a component which can fail easier than a relay coil (more self heating and less protective package). The Coil Ratings table in the spec sheet clearly allows 120% coil V at continuous du...

Thanks a ton, that spec sheet is really helpful. I knew that resistors were current-limiters, but I didn't know if they would protect something from voltage. Anyway, after reading your post I bought some 68 ohm resistors from Radioshack and we'll see how it works. I used 68 ohms because I want the m...