Hi,
I am v.new to electronics and helping my kid science school project.
We are trying to build a v.simple water level indicator. We have to use one of the 74xxx series I.C. So we decided to use NAND gate I.C (74LS00).
Circuit diagram is attached. It works fine in the breadboard when input of one gate is connected to (-ve) of the circuit the LED lights on. The problem is when we dip the wires in the water the light doesn't turn on.
I searched internet and it seems that in those cases one should put pull-up or pull-down resistors. Is that correct?
Can anyone please help us in this. His project is due next week and we can't figure out why it doesn't work in the water. Water supposed to be good conductor of electricity.
Much appreciated.
thanks,
I am v.new to electronics and helping my kid science school project.
We are trying to build a v.simple water level indicator. We have to use one of the 74xxx series I.C. So we decided to use NAND gate I.C (74LS00).
Circuit diagram is attached. It works fine in the breadboard when input of one gate is connected to (-ve) of the circuit the LED lights on. The problem is when we dip the wires in the water the light doesn't turn on.
I searched internet and it seems that in those cases one should put pull-up or pull-down resistors. Is that correct?
Can anyone please help us in this. His project is due next week and we can't figure out why it doesn't work in the water. Water supposed to be good conductor of electricity.
Much appreciated.
thanks,
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