I'm having problems with the LM339 comparator.I know there's dozens of questions about this device but none clears the air for me.
I know its an open collector output and needs pull up resistors to set it to high but here's my problem.I have the pull up,but the output is always set at 1.7V even when i use a different comparator.
The inputs Voltage V+ dependa on the intensity of the ambient light and vary from 0-4.8V and am supplying the comparator with 5V,I know the inputs shouldnt go too close to the supply magnitude but they rarely go that far.
Even if the input V+ goes to zero the output still stays at 1.7V its only goes to zero when i manually ground the input V+
Please help
I know its an open collector output and needs pull up resistors to set it to high but here's my problem.I have the pull up,but the output is always set at 1.7V even when i use a different comparator.
The inputs Voltage V+ dependa on the intensity of the ambient light and vary from 0-4.8V and am supplying the comparator with 5V,I know the inputs shouldnt go too close to the supply magnitude but they rarely go that far.
Even if the input V+ goes to zero the output still stays at 1.7V its only goes to zero when i manually ground the input V+
Please help
Last edited: