Adjustable resistor / indicator

1 General

2 Project description

I needed a way to experimentally find resistance that works best in certain circuits. Usual potentiometers could not handle required power dissipation and were not precise enough.

Solution is to build adjustable resistor:


Logically there is series of resistors that increase in resistance in the power of 2: 0.5, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512. Each resistor can be enabled or disabled by a switch. This makes entire range of 0 – 1023.5 ohms available with the 0.5 ohms precision.

Schematic: schematic.png

Here is front panel for switches: front%20panel.png


Sometimes I would like to use lightbulbs with various parameters as test load/indicator. Current device has 4 of them included.

Here is front panel for light bulbs: indicator%20panel.png


After assembly using prototype PCB: make,%202.png

Following body is used as a case and PCB support: body.png


Result: make,%203.png

Cover on the back: back%20cover.png

Download: STL file

Button covers: button.png