Decade Resistor Box

thingiverse

Human: Decade Variable Resistor Spanning from 1 ohm to 9.9 Mohms in increments of 1ohm is Made with a 3d printed enclosure using moderately priced and easily sourced components. The Total cost for the parts ordered looks to be just under €20, however soldering the assembly may be rather tightly packed and therefore requires some risk-tolerance. Resistor tolerances should be noted - 1% resistors are used in this project which offers better quality than 5% but also more affordable than a further upgrade to sub-1% options. Also worth noting is that the switches themselves add some variance in resistance so once the dial-in values for any circuit setup utilizing this device, removal of the enclosure prior to measuring final circuit resistance will produce a reading within +/- 1%. In fact due to switching effects adding around couple ohms to each low value setting (about 1.5 ohm per unit), low-resistance measurements might suffer from slightly increased imprecision while high-resistances will hold a higher precision overall. For those wanting precise final results on resistance value after setup tuning, best practice calls for disconnecting this readout device before recording readings in real time. Parts needed: *7 piece collection of 10 digit decimal switches * 2 banana plug connectors * A selection of 1% 1/4 watt resistors (9 units): each being in different ranges as per values below. Note simplified switch drawings are included here depicting resistance measurement procedures where in measurements should take place only between common and the wiper pin zero (0) location respectively which would be readout result R x 3 assuming it was configured as such. To attach additional switches together simply connect next resistor set's Common point to previous switch pins Zero then record readings appropriately according desired outcome for given circuit project needs