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How to Connect BJT and Mosfet with Arduino

In this article we elaborately discuss the correct methods of interfacing transistors like BJTs and mosfets with any microcontroller or an Arduino.

No matter how well programmed or coded your Arduino may be, if it's not correctly integrated with the external hardware, could result in inefficient operation of the system or even damage to the components involved in the system.

Therefore, it becomes extremely important to understand and learn the right methods of using external active components with a microcontroller, so that the final outcome is effective, smooth and efficient.

Before we discuss the methods, it would be useful to learn the basic characteristics and working of BJTs and mosfets.
Electrical Characteristics of a BJT BJT stands for bipolar junction transistor.

The basic function of a BJT is to switch ON an attached load in response to an external voltage trigger. The load is supposed to be mostly heavier in current compared to the input trigger.

Thus, the basic function…

Understanding Amplifier Circuits

In general, an amplifier can be defined as a circuit designed to boost an applied low power input signal into a high power output signal, as per the specified rating of the components.

Although, the basic function remains the same, amplifiers could be classified into different categories depending on their design and configurations.
Circuits for Amplifying Logic Inputs You may have come across single transistor amplifiers which are configured to operate and amplify a low signal logic from an input sensing devices such as LDRs, photodiodes, IR devices.

The output from these amplifiers are then used for switching a flip flop or a relay ON/OFF in response to the signals from the sensor devices. 
You may have also seen tiny amplifiers which are used for pre-amplifying a music or audio input, or for operating an LED lamp.
All these small amplifiers are categorized as small signal amplifiers. Types of Amplifiers Primarily, amplifier circuits are incorporated for amplifying a music frequency…

Learning Basics of Semiconductors

In this post we comprehensively learn regarding the fundamental working principles of semiconductor devices, and how the internal structure of semiconductors function under the influence of electricity.

Cellphone Controlled Dog Feeder Circuit

A GSM module and Arduino based dog feeder circuit is discussed in this post. The system can be used for operating a dog feeder mechanism through the owner's cellphone whenever it may be required.

Arduino Full-Bridge (H-Bridge) Inverter Circuit

A simple yet useful Microprocessor based Arduino full-bridge inverter circuit can be built by programming an Arduino board with SPWM and by integrating a few mosfets with in H-bridge topology, let's learn the details below:

 In one of our earlier articles we comprehensively learned how to build a simple Arduino sine wave inverter, here we will see how the same Arduino project could be applied for building a simple full bridge or an H-bridge inverter circuit.
Using P-Channel and N-Channel Mosfets To keep things simple we will use the P-channel mosfets for the high side mosfets and N-channel mosfets for the low side mosfets, this will allow us to avoid the complex bootstrap stage and enable direct integration of the Arduino signal with the mosfets.

 Usually N-channel mosfets are employed while designing full bridge based inverters, which ensures the most ideal current switching across the mosfets and the load, and ensures a much safer working conditions for the mosfets.

However whe…