I want to test my DS1804 digital potentiometer on breadboard. Ohmmeter shows about 25 kohm between H and L or W. I thought it will go down with this circuit when I push button but it doesn't work (resistance stays at 25 kohm). I connected +5 V on U/D but it's same.

Where is my mistake?


simulate this circuit – Schematic created using CircuitLab

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1 Answer 1


R1 should be connected to the /INC terminal, and the switch should be connected between the /INC terminal and Ground. This will ensure that the /INC terminal is a High unless the switch is closed.

Your circuit leaves /INC in an undetermined state when the switch is open, and High when the switch is closed. The wiper position will only be incremented or decremented when the /INC input changes from High to Low.

To move the wiper towards the H terminal, the Up/Down input must be High. When Up/Down is Low, the wiper moves toward the L terminal.

The resistance between H and L does not change - only the resistance between the wiper (W) and either H or L changes. W->H will decrease and W->L will increase as the wiper position is incremented.


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