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resistor multiple values

HI all,

Im trying to work out a resistor bank using DIL switches. Now I need a range such as 50k,100k,150k,200k and so on upto 1meg (50k steps) Now with 20 DIL switches I could select it like one of 20 and use 20 different resistor values on each switch, such as switch 1 is 50k, switch 2 is 100k, etc... though it got me thinking that could I do the same job with just 8 switches and just use maybe 2 switches on at the same time to get the same values.

It would be easy to start with since 50k could be got with 2 100k resistors (SW1 & SW2) maybe switch 3 could be 200k, so SW2 and SW3 would give me like

150K ? I dont know , my math aint to great, maybe someone can think of a easier way to do this or work it out ?

thanks, Chris

Reply to
exxos
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Five switches:

50K 100K 200K 400K 800K

and you can select any value between 50K and 1,550K (1.550M) in 50K steps.

--
John Miller
Email address: domain, n4vu.com; username, jsm

Every country has the government it deserves.
                -- Joseph De Maistre
Reply to
John Miller

100k,
8

same

can

I have been thinking in parallel for a row of switches. I assume this is series connection, which I guess could be possible though I dont see how to link such a arrangement.

chris

Reply to
exxos

is

how to

Wire all the switches in series and then solder the resistors across the switch contacts, viola. When a switch is closed, it's resistance is zero, when it is open, it's resistance is the value of the resistor across the contacts.

Reply to
Anthony Fremont

That would be between 0 and 1550K in 50k steps (all switches closed for 0)

:-)

Reply to
dirk

In response to what Anthony Fremont posted in news:KDGpc.102457$ snipped-for-privacy@fe1.texas.rr.com:

More like a trombone than a viola...

--
Joe Soap.
JUNK is stuff that you keep for 20 years,
then throw away a week before you need it.
Reply to
Joe Soap 

--
A trombone is more like a pot. :-)
Reply to
John Fields

Heh...now that you mention it...

...and a valved instrument (for the benefit of those who always wondered how three valves can produce so many notes) has valves that lower the pitch (lengthen the tubing) by different amounts, which can be combined, just like the resistors we're discussing:

1st valve:      whole step 2nd valve:      half step 3rd valve:      minor third

and in combination,

1-2:    minor third 2-3:    major third 1-3:    fourth 1-2-3:  augmented fourth/diminished fifth

John Miller Email address: domain, n4vu.com; username, jsm

My favorite sandwich is peanut butter, baloney, cheddar cheese, lettuce and mayonnaise on toasted bread with catsup on the side.                 -Senator Hubert Humphrey

Reply to
John Miller

ahhhh, the Euro has dropped! Never thought about doing it that way, thanks!

I also noticed this thread has drifted off topic after only 2 posts ;-)

Cheers, Chris

Reply to
exxos

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