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| Binary (additive) resistor or capacitor box |
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| eti:
Has anyone ever made a resistor or capacitor box (thumb wheel selectable increments) which works like this: [jumper 0 ohms] [1 ohm] [2 ohm ] [4 ohm] [8 ohm] [16 ohm] [32 ohm] [64 ohm] [128 ohm] You'd have all those resistance values and switch them in and out of series with the other resistors to additively create any ohmic value from 0 ohms to 255 ohms. To do the same for capacitors, you'd just switch the values in and out of parallel connection with the others. This is binary of course. I hardly think this could be a new thing I'd thought of. Ideas? |
| Ed.Kloonk:
Use a 8 position dip switch. https://www.ato.com/8-position-dip-switch The sub 10 ohm setting precision might drive you bonkers. |
| eti:
--- Quote from: Ed.Kloonk on December 11, 2022, 06:56:02 am ---Use a 8 position dip switch. https://www.ato.com/8-position-dip-switch The sub 10 ohm setting precision might drive you bonkers. --- End quote --- Hence me saying thumb wheels would be used. Yeah it would be a silly design to use DIP switches. |
| ledtester:
Teardown of a IET Decade Resistance Box at 3:00: EEVblog #211 - IET Decade Resistance Substitution Box -- EEVblog https://youtu.be/37gYHdY0DAM?t=3m It uses only 5 resistors per decade in a 1-2-2-2-2 pattern. It uses a custom wiper pattern to accomplish this. I recall there being a project discussed on the forum where a custom pcb was developed for an existing thumbwheel switch and then you could get that pcb manufactured at pcbway/jlc pcb/etc. to create some sort of substitution box -- can't seem to find it at the moment. |
| Ed.Kloonk:
--- Quote from: ledtester on December 11, 2022, 07:52:38 am ---Teardown of a IET Decade Resistance Box at 3:00: --- End quote --- I had forgotten about that. Gee, you're resourceful. |
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