We have used 10uF capacitor C3В to get the highest gain i.e. PIN 1 and 8 :В These are the gain control PINs, internally the gain is set to 20 but it can be increased up to 200 by using a capacitor between PIN 1 and 8. Pinout and Pin description of LM386 audio amplifier ICВ is given below. To connect the IC in breadboard or soldering in veroboard, we need to know the pin diagram of the Power Amplifier IC LMе…ѓ86. We need to be careful about this rating otherwise we could damage the power amplifier or the output speaker. Other circuitry and connections remain the same in our construction.ДЄlso, the power amplifier can drive the wide range of load, from 4 Ohms to 32 Ohms and can be powered using 5V to 12V. We used a common but close value of 0.047uF instead of 0.05uF. This RC combination is called as snubber or clamp circuit which protect the amplifier from back EMF, produced by the speaker. There is a 0.05uF capacitor along with a 10R resistor. We have changed the value and used 470uF instead of 250uF capacitor. Also, the 250uF capacitor is connected across the Speaker. We did not change the gain of the amplifier in our circuit construction. The 10uF capacitor across pin 1 and pin 8 is responsible for the 200x gain of the amplifier. The amplifier will provide 200x gain at output depending on the input.

In the circuit diagram, the Amplifier is shown with the respective pin diagrams. We removed the 10k pot section and added additional bias circuitry of the microphone amplifier. The circuit is exactly same as shown in the LM386 datasheet from Texas Instruments. The schematic for simple Microphone to Speaker circuit is given below вЂ“ If you are interested in Vero board the following things will be additionally needed.

We need the following things to make the simple microphone amplifier. A simple amplifier circuit can also be constructed with transistor without using any amplifier IC.

If you are interested in amplifiers then check our other Audio Amplifier circuits. In this project, we will make a small microphone amplifier using an LM386 power amplifier which is enough to produce loud audible sound out of a ВЅ Watt, 8 Ohms loudspeaker. So, what is the solution? It is easy, we need to add a preamplifier, possibly Power amplifier or both to make something useful and to produce a louder sound from the output speaker. On the other side, speaker needs huge current with large amplitude to produce enough movement and to generate the audible loud sound. The electrical output across the microphone provides a tiny amount of current which is too small to do something useful out of it and the amplitude is also low. It is true that the microphone produces electrical energy but it is not sufficient to drive the huge load, that is speaker. So can we directly connect the microphone with the speaker? Like the image below? We know that a speaker converts Electrical energy into mechanical energy and produce a sound wave, and we also know that, the microphone does exactly opposite thing which produces electrical wave from the sound signal. Most common types are Dynamic Microphones, Condenser Microphone, Piezo electrical microphone etc.ДЄ condenser microphone uses a diaphragm which vibrates and used as a capacitor plate to produce electrical signal variations, whereas dynamic microphones are use moving coils to change a magnetic field and produce the electrical signal. Depending on this component and the method to convert the sound wave into Electrical signal, there are various type microphones are available in the electronics and sound engineering field. A microphone has a sensitive component which converts the air pressure variations created by the sound wave into electrical signal.

Use a speaker as a microphone