DIP/SIP resistors

[John Gutmann]

does any body know where to get DIP or SIP resistors and how to use them?

[Matt Leese]

Originally Posted by sparksandtabs

does any body know where to get DIP or SIP resistors and how to use them?

My experience with using resistors in a DIP or SIP environment has been that the resistors are standard two terminal resistors that have been soldered onto a DIP or SIP carrier. Usually five or six resistors can be placed on one. I believe they're for-sale on McMaster Carr.

If you are having more problems with this, drop me a line in two weeks when I'll be back in Rochester.

Matt

[KenWittlief]

www.Digikey.com

they are not exactly soldered onto the carrier, they are formed from a single piece of material, so one of the benefits is they tend to be very close to each other in value (where impedance matching is important)

other than that, its just a convenient package when you need 4, 6, 7 or 8 resistors all with the same value, like pullup resistors on a bus for example.

[Al Skierkiewicz]

Be aware that these packages are available in different configurations. Some are individual resistors with both leads brought out or they are available with one side of the resistors in common to a single pin. This helps when you are planning to use them for pullups on digital inputs. In analog circuits, as Ken has pointed out, resistor groups can be optimized for better precision than 1% and are often used when designing op amp circuits that require tight gain matching and the best common mode rejection, differential amplifier charachteristics and temperature stability. The Digikey catalog has some of the wiring styles available and often will link to manufacturers websites for further details.

[Andy Brockway]

Al,

In this thread you use multiple resistors for the switch.

Originally Posted by Al Skierkiewicz

.....We use a modified Radio Shack 2 pole 6 throw rotary switch to make a nice 11 position switch for program sub calls. The 11 positions have 10 9k (90K series resistance) resistors between them with a final 9K in series with the switch. At position 1 the resistance is 99k at postion 11 the resistance is 9K.

Is this a good place to use a SIP resistor network?

[Al Skierkiewicz]

Andy,
It is not essential to have matched resistors in that application since you want the code to be a window comparator to handle variations in power supply voltage. If you had an application that only used part of a network and you had just enough left over for a switch(es) that would be an efficient use of components. The switch we use from Radio Shack is designed for wire so we used 1/4W resistors wired to the switch terminals and then we only had to bring back two wires to the analog joystick input. We had to mechanically modify the switch by removing a stop and that allowed a six position switch to fully turn to 11 positions. (It also reguires the removal of one of the wipers. It isn't pretty when you're done but it works well for our purposes.

[Andy Brockway]

I know this is a little off topic....

I bought that switch and the resistors last year but we never built it. I do not want to tie up so many digital inputs this year so I am exploring this alternative. I see that Jameco has an eleven detent 100k pot in their catalog. Any thoughts on this pro/con?

[Alan Anderson]

Originally Posted by Andy Brockway

I see that Jameco has an eleven detent 100k pot in their catalog. Any thoughts on this pro/con?

That looks like a pretty sweet solution, if the detents are sufficiently heavy. I'm not sure a torque of "100-400gf.cm" would be enough to keep it from getting bumped too easily; it's designed as an analog control knob, not a multiple-position switch.

[Al Skierkiewicz]

Andy,
I don't know if the pot would work as great as the switch. I have used these pots for volume controls and they are not repeatable as the switch it. The detent is accomplished by a disk with bumps on it. (just stamped out part)
They also have an 12 position switch that looks identical to the Radio Shack part. We put a round knob and it is not easily bumped. All it selects is a different auto mode. The program looks at the switch value (voltage) and jumps to a different routine on that basis. We have used this method for three years now.

[KenWittlief]

Originally Posted by Andy Brockway

I know this is a little off topic....

I see that Jameco has an eleven detent 100k pot in their catalog. Any thoughts on this pro/con?

that is the "Nigel Special", used only on custom Marshall Guitar amplifiers!

the Spinal Tap boys effectively tap into, such as the scene in which Nigel Tufnel (Guest) proudly displays the band's instruments and equipment, which include a guitar so special it can never be looked at, let alone played, and a Marshall amplifier that "...goes to 11" whenever the band needs a little extra kick.