4 Aug Hello everyone! I hope you all will be absolutely fine and having fun. Today, I am going to share my knowledge about Introduction to LM The LM is a power audio amplifier for consumer applica- tions. In order to hold system cost to a minimum, gain is internally fixed at 34 dB. A unique input. The LM is a power audio amplifier for consumer applica- tion In order to hold system cost to a minimum gain is internally fixed at 34 dB A unique input stage.

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Because of the high lm830 of IC audio amps, it is highly recommended to isolate them from the power supply to prevent oscillations. Output capacitor coupling is mandatory in just about all IC audio amp designs. While many experimenters have stayed away from these little black mysteries, I am going to uncover some of their secrets and demonstrate how easy they are to use.

Input signals are normally fed to the non-inverting input while the inverting input is normally tied to ground. The primary advantages of the LM series IC’s are higher output power, very low distortion and low external parts count.

IC’s offer many advantages including high efficiency, high gain, low standby current, low component count, small size and ,of course, low cost. This IC can become quite warm and it’s important to get rid of excess heat through the pins. This configuration will give us a gain of Experience has shown the LM should be soldered directly to the circuit board no IC socket if it is going to be operated at its full rated 2 watt output.


My experiences with this IC revealed that it must be heat sinked at all times due to it’s high standby current.

This IC offers low ln380 and is a real bargain compared to discrete transistors. The LM comes in an 8 pin package and its basic circuit is virtually identical to the LM except for the different pin out.

Integrated Circuit Audio Amplifiers

In this circuit, R1 and C1 lm830 this task very well. It is little wonder that audio amp IC’s have replaced discrete transistors in most consumer electronic devices. It is important to understand that increasing the gain does not increase the output power.

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Just like regular op amps, audio amp IC’s have an inverting ln380 non-inverting input. No matter how much volume, an audio amp provides, there are still those who require even more.

For example, check out National Semiconductor at http: If you plan to use this IC keep all components as close as possible to the IC and be certain that your power source can supply up to 1.

The LM comes in a 14 pin package and pins 3,4,5,10,11 and 13 are connected to ground to act as a heat sink. In a previous article I discussed building audio amplifiers using discrete transistors. There are many other audio amp IC’s available to us and data sheets can be easily obtained by searching the world wide web.


It should be apparent now that audio amp IC’s have much to pm380 us in the way of low cost audio amp circuits.

Almost all of the major IC manufacturers now offer their data sheets to be downloaded free at their web sites. Perhaps the most unique feature is that it is available at any Radio Shack and can operate at voltages as low as 5 volts. Resistor R3 controls the gain and Capacitor C3 couples the output to the speaker.

While it is possible to build good audio amplifiers from discrete transistors, they lj380 no match for the many audio amp IC’s available to us. The type sold by Radio Shack is the LM and is the one we used in this circuit.

The circuit in Figure 4 uses a LM IC amp and will provide up to 7 watts of output power for those who want to really experience their audio.

The increased gain is only used when a very low input signal is to be amplified. The main advantage to this IC is its 7 watt output which is why it has found its way into many inexpensive car pm380.

By removing R2 and connecting C2 across pins 1 and 8, we can increase the gain to