# What Is LM339?

In this tutorial, we discussed LM339 Pinout, Voltage Comparator using LM339 IC, and LM339 Datasheet with neat sketches. All electronic circuits projects are available on this website circuits99.com

The LM339 is Quad Comparator, which is an analog comparator and voltage reference. It is often used as a voltage comparator or to provide a reference voltage for other components. The LM339 IC is an adjustable quad comparator and its works with a single supply. It can be used for comparison circuits to provide an output signal when a certain condition is met. It is a very popular analog circuit that can be used as a voltage comparator, as a current sensor, and as a temperature sensor.

## LM339 IC Voltage Comparator

LM339 IC Voltage Comparator Circuit Diagram

The above Circuit works on comparison between two voltage V1 and V2 as shown in the figure. This LM339 IC works on a single supply voltage source ie Vcc.

The above circuit comparison of outputs are,

If the voltage V1 is greater than V2 then Output voltage (Vo) is equal to Vcc

V1>V2 then Vo = Vcc

If the voltage V2 is greater than the V1 then Output Voltage (Vo) is equal to  Zero Voltage (0V) or GND

If V2>V1 then Vo = 0V or GND.

Based on the state of the output we can determine whether V1 is higher or V2 is higher at the input.

The LM339 is especially useful because it can be used to detect when a signal is either too high or too low. This allows you to use one signal to produce two different outputs.

### LM339 Pin Details

 Description Pin and Name The output pin of comparator 1 Pin 1, 1Out The output pin of the comparator 2 Pin 2, 2OUT Power supply Pin 3, VCC Negative input pin of the comparator 2 Pin 4, 2IN- Positive input pin of the comparator 2 Pin 5, 2IN+ Negative input pin of the comparator 1 Pin 6, 1IN- Positive input pin of the comparator 1 Pin 7, 1IN+ Negative input pin of the comparator 3 Pin 8, 3IN- Positive input pin of the comparator 3 Pin 9, 3IN+ Negative input pin of the comparator 4 Pin 10, 4IN- Positive input pin of the comparator 4 Pin 11, 4IN+ Ground Pin 12, GND The output pin of the comparator 4 Pin 13, OUT4 The output pin of the comparator 3 Pin 14, OUT3

### LM339 Datasheet

If the above link not working you can download here for LM339 datasheet pdf format