# what is a logic probe and how does it work?

## what is a logic probe?

Did you knew what is a logic probe? In this article admin will share about how to make logic probe using led. But before making it you must know first what a logic probe is

logic probe is a tool that is used to check input or output condition in digital circuits

A logic probe is required when you check on the digital circuit such as an IC expecially for TTL or CMOS. The results can be seen from the logic probe is logic 1 and 0 or high and low conditions

You can make a logic probe using led 2 pieces so that each color will display condition 1 or 0

## how to make a logic probe using led and how does logic probe work?

To create a logic probe you requires 2 led this time admin using red and green color pal you can replace it with another color as you wish

read also articles what is LED and how does it work

in the following sequence red Led serves to display high or logic conditions 1 whereas the green led is used to display low or logic conditions 0

As if the red and green led simultaneously it means the pin that the detection is in a floating condition that is a condition that is prohibited in the digital circuit

condition high or condition 1 is condition where an input or Output is connected with Vcc or positive voltage where condition low or condition 0 is condition where an input or Output is connected with ground or negative voltage

examples of high conditions in digital circuits

examples of low conditions in digital circuits

Well logic probe is used to detect a certain point on the circuit whether it is logged high or low

led red lights indicate a point in high condition whereas if the green led is indicating that it is in low condition, if it is lit together then it is in a floating condition. For Logic probe then ground circuit with ground logic probe must be combined

Read also an article about what is DTMF and how does it work?

Logic probes in high-light red light conditions

Logic probe under low green light conditions

Please note that led has a working voltage of 2-3V so the above circuit can only be used to detect high and low conditions at 5V voltage