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This document was written by Chris Hansen.

For more information, or to purchase the products shown here, please visit our web site:

www.hansenhobbies.com

A Brief Discourse on Connector Antics

When we started producing electronics we soon found ourselves buried in tens of thousands of connectors that we knew

would be slow to move. We started selling connectors and wire as kind of an afterthought, hoping it would reduce our stock

and bring in a few extra bucks. Since we started our connector sales have gone up by leaps and bounds. Based on the load of

email questions I decided to write a comprehensive document on the connectors we sell. For the most part this is targeted

at radio control hobbyists but I’m very aware that many of our customers buy connectors for entirely different applications,

so I’ll try and keep it somewhat generalized. Also, I’ll attempt to make this an honest tutorial rather than an advertisement

for our products. Hopefully you’ll find this document useful; I’ll add to it as I find time.

-Chris Hansen 4/17/2009

Servo Connectors and .1” Connectors

In the electronics industry, connectors are most commonly referred to by the spacing between contacts. The most popular size, without a

doubt, is the .1” connector. Open up any computer and you’ll find tons of .1” connectors from IDE cables to USB and Firewire headers. That’s

exactly the type of connector used by the RC industry for servos and anything else that plugs into your receiver. For the most part, anything

said about a .1” connector applies to servo connectors and vice versa.

First, let’s begin with a little terminology. The

housing

is the

plastic part of the connector. It houses the

terminals

which are

the metal contacts (often gold or tin plated) which make the

actual electrical connection with whatever you’re plugging into.

Terminals are

male

female

, and as is often the case, both

work with the same housing as seen in the image below (there is

no male or female housing). Connector gender is where the RC

industry seems to be backwards from the rest of electronics.

In this document, and on our web site, I take the more

traditional (and in my opinion, more sensible) approach and call a

connector based on the type of terminal it has. If it has female

terminals, as found on anything that plugs into your receiver, I

call it a female. This is the naming protocol used by pretty much

every other electronics field. Keep in mind, however, that most

other resellers and RC hobbyists will refer to connectors

exactly the opposite as I do. Sometimes I take a very neutral

route and instead of using gender names just say, “servo end”

and “extension end”.

Terminals:

We highly recommend using only gold terminals for your connectors. Tin

plated contacts usually have a life of about 10 cycles (a cycle being plugging

in and unplugging) before the contact goes outside of its rated specs

(possible specs being contact resistance and holding strength). Basically,

the plating starts to rub off and the contact becomes prone to oxidation,

and the contact(s) start to lose their springiness, increasing contact

resistance. “Contact resistance” refers to electrical resistance, which can

impede power going to the servo and possibly disrupt the servo signal. In

most electronics applications the connector would be plugged in once and

never touched again, so 10 cycles would be fine, but they’re simply not

meant for the repeated use seen from hobbyists. Gold connectors have a

life of 50-100 cycles, offer lower contact resistance, and are extremely

resistant to corrosion. These numbers probably still seem low but keep in mind that the contact isn’t going to fail after 100 cycles, it will just

gradually increase in contact resistance and decrease in holding strength (the springiness of the contacts is reduced). If your connector

doesn’t plug in firmly anymore, that’s a good indication to replace it.

Summary of content (11 pages)

PAGE 1
A Brief Discourse on Connector Antics When we started producing electronics we soon found ourselves buried in tens of thousands of connectors that we knew would be slow to move. We started selling connectors and wire as kind of an afterthought, hoping it would reduce our stock and bring in a few extra bucks. Since we started our connector sales have gone up by leaps and bounds. Based on the load of email questions I decided to write a comprehensive document on the connectors we sell.
PAGE 2
Housings: The electronics industry commonly uses plain symmetrical connectors which have a rectangular profile. Radio manufacturers like Futaba, JR, and Hitec have opted to make their connectors somewhat unique by making them polarized; in other words, they only plug in a certain orientation. This is achieved by beveling the bottom edges (as with JR/Hitec) and/or adding a keyed edge (as with Futaba).
PAGE 3
about is if you need to be concerned about the weight of the wire. Last, keep in mind that 22-24AWG wire is just plain easier to work with than anything much thicker or thinner. One of the most irritating things you’ll find when buying servo wire is that the listed wire sizes never seem to be consistent with what somebody else is selling.
PAGE 4
Stripping Wire: I prefer the type of wire stripper with several size teeth in a row. This is the type we sell on our website. The reason I like it (besides having used this kind all my life) is that you can quickly strip servo wire with it. It isn’t meant to be used like this, but I find this method works great: 1) First separate the wires using the cutting part of the jaw as shown. 2) Position the wires in the first three teeth and close the jaws. 3) Flip the wire over and close the jaws again.
PAGE 5
Crimping Tools: We currently sell two tools to crimp terminals, again dubbed “Economy” and “Deluxe” crimping tools. Both tools have their pros and cons. Here’s a straightforward review of each: Economy Crimping Tool: The economy tool makes a good crimp but requires a lot of squeezing power which translates into sore hands after a while. It tends to bend the terminal a little when crimping so it has to be bent back straight. Also, the terminal may not readily release from the teeth.
PAGE 6
Making a Female Servo Connector With the Economy Crimping Tool: Whichever housings you decide to use, making the connector is the same. The gold terminals we sell fit all of the .1” and servo connectors we sell. Here I 1) 2) 3) 4) 5) 6) 7) Strip the wires as describe above. Set a female terminal in the larger set of teeth and close the jaws to lightly hold it in place. Do not press down.
PAGE 7
Making a Male Servo Connector With the Deluxe Crimping Tool: A male servo connector is very similar to a female connector, just don’t forget to reverse the order of the wires. The same housing is used, along with male pins instead of female pins. That’s right, it’s the exact same housing for the male connector. Then, if you choose to, you can finish it off with a protective plastic sleeve as found on pretty much all male connectors in the RC industry.
PAGE 8
Inserting and Extracting Terminals: Typically, the terminals will easily slide into the housings and snap in place. Sometimes I find that when using thicker wire the rear set of wings on the terminals sometimes out a tad too wide, and the terminal has trouble sliding into the housing.
PAGE 9
Female to Male Adapters: We sell these little 3pin adapters to let you turn a female connector into a male connector. They can be very handy, as they allow you to plug two female connectors together as shown below. You may choose to work only with female connectors and avoid male connectors altogether. If you’re a electronics builder you’ll be very happy using these to plug female connectors into a breadboard.
PAGE 10
Resistance and Voltage Drop Since I get so many questions/comments on wiring for high demand applications like highdraw systems, high torque digital servos, long servo leads, and quality of contacts, I though I would write a section that talks about power considerations in these situations. Resistance in the System: In order to keep your servos and electronics working at their best, you need to keep the resistance down in your connections.
PAGE 11
Other Thoughts Here I’ll just write some random ideas as I think them up. The Truly Universal Connector: Universal servo connectors are named so because the female connectors will plug into any receiver. The only problem is that a female Futaba J connector can’t plug into a universal shrouded/sleeved male connector because the key gets in the way and it may not have bevels.