Jon Gerow · 06-26-2006 · Category:
The resistance of modular connectors, adapters and splitters
Years ago, there was this
cat named Ohm and he explained to us that resistance sucks.
Ohm’s law, as it
pertains to resistance in electrical current, is R (resistance) X A (amperage)
= V (voltage.) So you can see, the greater the resistance, caused by either
length of wire, gauge of wire or having to go through connectors and/or the
greater the current, the less voltage you get.
In simple terms, having
a modular power supply may drop your voltage a little because of the resistance
between the modular interface and the cable. And using a 20-to-24 pin adapter
or any kind of splitter can cause a slight drop in voltage because of the
resistance caused by any imperfect contact between the pins of such an adapter
or splitter. But on that same note, every single connection you make (PSU
to drive, or motherboard, or video card) is another connector that is going
to create a little more resistance.
There’s been a lot
of scare tactics used to convince people not to go with a modular power supply.
And even though there are some valid points made, the reality is that the
resistance is quite minimal even at high loads...if the modular
power supply is a well thought out design and preventative measures are taken
by the user.
For example: A PCI-e cable
is going to have less resistance if there’s 3 12V leads on each side
of the cable and 3 grounds on each side of the cable. Unfortunately, some
modular power supplies may only have one or two wires split into three for
each row for a PCI-e connector, so some homework needs to be done on how
the cables are constructed when considering a modular power supply.
And when using a modular
power supply, adapters or splitter, make very certain that the connection
between both interfaces is secure, firm and flush. Make sure all of your
connectors are fully seated. This does not only apply to modular power supplies,
but also goes for standard power supplies and all of the connections you
make to the motherboard, your drives, etc. If you have a connector that is
not fully seated, you create resistance. That resistance not only can cause
a drop in voltage at the end of that particular wire, but also create heat.
Many times I have seen BURNT connectors from cables not being plugged all
of the way into their sockets.
On the subject of gold
plated contacts: They don't do any good unless they're interfaced with gold
plated connectors. In fact, the mating of dissimilar metals is actually more
prone to corrosion than if both connectors were tin plated (your typical
silver colored connector.)
So if you get a modular
power supply that boasts gold plated connectors, keep in mind that it may
only be better to have gold on the power supply side of the cable, and only
if the modular interfaces on the power supply are also gold plated. Since
I personally haven't seen any hard drives or motherboards with gold plated
power connectors, I'll pass on gold plated connectors on the peripheral end
of the cable.
- The PC power supply:
- The PC power supply label:
- Defining the connectors of an ATX power supply
- ATX power supplies DO NOT turn on at the flip of a switch
- Testing your power supply's voltage: Software vs. Multimeter
- Power Supply Efficiency
- The Derating Curve
- Power Factor Correction
- The resistance of modular connectors, adapters and splitters