LM358 IC and Its Applications
Today, In this blog, you'll learn about the most used IC in electronic sensors & many other circuits i.e. LM358 and How you can use it in your various DIY electronics projects.

The LM358 contains two independent high gain operational amplifiers, low power, dual-channel op-amp. It can handle voltage from 3V to 32V DC supply and current up to 20mA per channel.  As it is a single supply, It eliminates the need for a dual power supply, thus simplifying design and basic application use. A drawback of it is that the single supply does not offer a negative voltage supply. Due to this, the output will not be able to go below 0 volts.

LM-358 has a lot of amazing features including, wide supply ranges, low supply current drain, independent of supply voltage, wide unity-gain bandwidth, input common-mode voltage range including ground, low input bias, and open-loop differential voltage gain, internal frequency compensated for unity gain etc. 
The LM 358 has several applications, including operational amplifier (Op-amp) circuits, transducer amplifiers, DC gain blocks, comparator circuits, Active filters, current loop transmitters for 4 to 20mA and so on.

Pin Number

Pin Name




This is the output pin of the Op-Amp 1



Inverting Input pin of Op-Amp 1



Non-Inverting Input pin of Op-Amp 1



This is the Ground pin of the IC. It needs to connect to the Negative(-) terminal of Supply Voltage.



Non-Inverting Input pin of Op-Amp 2



Inverting Input pin of Op-Amp 2



This is the output pin of the Op-Amp 2



This is the positive pin of the IC. It needs to connect to the Positive(+) terminal of Supply Voltage.

Operational Amplifier

An operational amplifier, or op-amp for short, is a DC coupled high gain voltage amplifying device that is useful for signal conditioning, DC amplification, filtering, and use with external feedback components like as capacitors and resistors between its output and input terminals.
The op-amp performs multiple functions based on its feedback configuration, whether resistive, capacitive, or both, and can be used as a differential amplifier, integrator, or summer.

LM358 as Comparator

In electronics, a comparator is a device that compares two voltages or currents and outputs a digital signal indicating which is larger. It has two analog input terminals, V+ and V- and one binary digital output that is low when V- is greater and high when V+ is greater. 
The LM358 comparator IC consists of two inbuilt operational amplifiers (Op-Amp), which means two comparators in a single IC.
To use LM358 as a comparator, we need to connect the power source with the Vcc and GND pin of the LM358 IC to activate the IC. Then, we need to provide two input voltages to the Op-Amp for comparison. Now, we can get an output from the Op-Amp.
To understand it more clearly, let’s see the working of circuits below.

Digital Dark Sensor Using LM358


The LDR is an electronic component whose resistivity changes as light is incident on it. when light is incident on it the resistivity decreases and When no light is incident on it the LDR offers the Highest resistance, thereby generating a signal across the non-inverting terminal of the Op-amp that is used to light up the LED when darkness is detected.

The sensitivity of the circuit can be changed by varying the 10K potentiometer if the LED remains ON even when no darkness is detected, you can turn preset until the LED turns OFF.

12V Battery Monitoring Circuit

Battery Level Indicator Circuit Using Dual Op Amp IC LM358 to Monitor the 3 important levels of a battery i.e. Low, Normal, and Full.
Battery Monitor- hnhcart.com


The circuit monitors the 12V battery voltage and displays the battery's charge status, with an indicator of low voltage/normal voltage/full voltage by glowing up the corresponding LED. The potentiometer adjusts the value where the red/yellow and yellow/green LEDs are turned ON or OFF. The red LED, for example, turns on at 11V and the green LED at 12V. Then the yellow LED remains lit until the battery voltage remains greater than 11V and less than 12V. With slight modifications, this circuit can also be used to monitor 4v, 6v, 24v, and other voltages.
Battery monitorDark sensorDigital sensorLm358

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