Introducing LM358 operational amplifier IC
An operational amplifier gets its name from the original use of opamps in analog computers for mathematical operations. Op amps typically have two differential inputs and a single output. Non-inverting input is called V+ and inverting input is designated V–. LM358 is a low power dual operational amplifier integrated circuit. Power supply voltage can range from +3 to +30 Volts and input voltage can range from -0.3 Volts to supply voltage.
AOL or open-loop gain of operational amplifiers or the gain in the absence of an external feedback loop from the output to the input is very high, of the order of 100,000. Because of this very high gain, even small microvolts of difference between V+ and V– may drive the amplifier into clipping or saturation. μA741 was a popular early integrated op amp which was introduced prior to LM358 and I had the chance to use it during my early years in hobby electronics.
LM358 consists of two independent high-gain op amps which can operate from a single power supply over a wide range of voltages. Power supply drain is low and independent of the magnitude of the power supply voltage. They have large DC voltage gain of the order of 100 dB which corresponds to 100,000 mentioned earlier. Standard 5V USB power supply is also suitable for LM358. It has an 8-pin DIP package (DIP8). As LM358 has two op amps, pinout will show two sets of inputs and outputs. Pin 4 is ground and Pin 8 the positive supply voltage. Pin 2 is the first inverting input and pin 3 the first non-inverting input. Pin 6 is the second inverting input and pin 5 the second non-inverting input. Pin 1 is the first output and pin 7 the second output.