Nixie driver K155ID1

Thread Starter


Joined Apr 14, 2021
I want to test my IC's without using the nixietubes first. whenever i put the inputs on how i want them i dont get the output i want. If all my inputs are set on low which i do with a microcontroller (nucleo f303k8) the output which is port 16 has a voltage of around 1.3 V while port 15 (which should have a high output when only input A is high) has a output voltage of around 1.7V.

Does anybody have an idea what i am doing wrong here?


Joined Jan 8, 2017
Your post is not very clear. You say " If all my inputs are set on low " it seems to be a contradiction. On normally means a high level. Off normally means a low level. For your KD1551D1 which seems to have the same datasheet a a 7441 a logic low is anything less than 0.8 volts and a logic high is between 2.0 volts and 5 volts. The outputs on the KD1551D1 are active low (They are open collector outputs which means thy need pull up resistors if not connected to the cathode of a nixetube.) Without a pull up resistor the outputs will not show a voltage change. Also you will need to check the data sheet on the nucleo f303k8 to see if it's outputs are capable of pulling the inputs of the KD1551D1 low.