The open loop buck converter designed in the previous tutorial did not had a regulated output. The output voltage was varying with the resistance of the load. The output of the circuit designed in the previous tutorial could be regulated by adding a feedback circuit in it. The feedback circuit could help in error detection of the output voltage and change duty cycle of the frequency on which circuit operates to provide a constant output voltage irrespective of the load resistance. Contrary to Linear Regulators which step down the DC voltage by dissipating the heat, Buck Converters step down the DC voltage through switching regulators and also step up the output current. According to the law of power conservation, input power must be equal to output power.
The designing of Boost Converter SMPS has been already discussed in the previous tutorials. In this tutorial, an open loop buck converter SMPS will be designed. The Buck Converter is also one of the topologies of the SMPS (Switched Mode Power Supply). These type of SMPS steps down the DC voltage unlike the Boost converters step up the DC voltage. So the buck Converter is also a DC to DC step down converter in which the output voltage is always less than the input voltage. Contrary to Linear Regulators which step down the DC voltage by dissipating the heat, Buck Converters step down the DC voltage through switching regulators and also step up the output current.
The closed loop boost converter designed in the previous tutorial though had a constant and regulated voltage at the output but it could not be varied. For a stable output that Boost converter had an error detection circuit. The error detection was done by adding a feedback circuit which continuously checks the error in the output voltage and provided a regulated voltage at the output. For making the output of the circuit adjustable, it must be drawn through a variable resistor. This closed loop boost converter not only had a feedback circuit, its output is also adjustable. Therefore in this tutorial, a closed loop non–isolated boost converter is designed.
The open loop boost converter designed in the previous tutorial had a fixed output voltage respective to the input voltage level. The output voltage of the circuit can be made variable by drawing the output through a variable resistor. The output voltage in this circuit still remains unregulated as no feedback is used.Therefore in this tutorial, an open loop non–isolated boost converter is designed. The boost converter can be designed in two ways- Open loop boost converter and closed loop boost converter. There are certain design parameters involved in the designing of the boost converter. It is important to understand these design parameters. Any boost canverter can operate in either of the two possible modes of operation.
The open loop boost converter designed in the previous tutorial did not have constant and regulated voltage at the output. For a stable output, a Boost converter with error detection circuit needs to be designed. The error detection can be done by adding a feedback circuit which continuously checks the error in the output voltage and provides a regulated voltage at the output. Therefore in this tutorial, a closed loop non–isolated boost converter is designed. The boost converter can be designed in two ways- Open loop boost converter and Closed loop boost converter. In the former, there is no feedback from output to input contrary to the closed loop which has a feedback circuit. So, the output of an open loop boost converter is not regulated. In the latter, there is a feedback from the output to the input. So, the output of a closed loop boost converter is regulated.
In this tutorial, an open loop boost converter SMPS will be designed. The Boost Converter is one of the topologies of Switched Mode Power Supply (SMPS). It has a DC source as Input power like a battery, generator or rectifier. In the case of a boost converter, the output power is always greater than the input power.So, the boost converter circuit will step up the power from one DC level to a higher DC level. The method of converting one DC voltage to a different DC voltage is called DC to DC conversion. The boost converter is a DC to DC converter which steps up the input signal to the higher voltage level.
The power supplies are the mainstay of electronic circuits. The power supply circuits can be designed in many ways. There can be adjustable power supplies or can be fixed voltage power supplies. A power supply circuit is rated by the voltage or range of voltage it supplies and the maximum current it allows to draw by a load. Secondly, the households are provided with AC voltages as main supplies. A lot of electrical appliances like fans, fluorescent tubes, and others are capable of using AC voltages directly but most of the electronic devices require conversion of AC voltage to DC voltages for their operation. Any external power supply circuit needs to convert AC voltage to DC voltage for use by the electronic devices. In this project, an adjustable power supply circuit is designed which inputs AC mains and provides 0 to 30V 2A DC Voltage as output.
In the previous project, an adjustable power supply circuit having an output voltage in the range between 0V and 30V with the maximum current capacity of 2A was designed. A lot of times required DC supply should have both positive and negative voltages. In the previous project, the negative voltage could be provided to a device only by reversing the terminal connections manually. The circuit will input 220V-230V AC and generates a variable DC voltage in the range of +/- 1.25 V to +/-22V at the output. This power supply can provide a maximum current of 1A at the output. For making an adjustable power supply that would have both negative and positive voltages, a center tape transformer needs to be employed in the circuit design.
This project aims to build an adjustable 0 to 15V 1A power supply circuit. The circuit will work as a portable mini power supply for most of the electronic gadgets. The circuit could be used as power adaptor for smartphones, wearables, and computer gadgets. In this project, an adjustable regulated symmetrical positive power supply is designed.For reducing any fluctuation and ripples at the output the supply needs to be regulated so that it can provide a constant voltage at the output. Again like previous projects, the voltage is adjusted using a variable resistor. This power supply provides regulated as well as the adjustable voltage at the output.
In the previous projects, adjustable power supply circuits were designed. Sometimes, the voltage to drive a specific circuit is already known and power supply circuit to output a constant voltage needs to be designed. In this project, a constant 12V power supply circuit is designed with an aim to power LED circuits.The circuit needs to be designed in a way that it should be void of any fluctuations or ripples. The circuit will input supply from main AC supplies and will convert it to a ripple free 12V DC supply. The circuit will be able to draw a maximum current of 1A.
In the previous project, a constant 12V DC power circuit with current limitation of 1A was designed. In this project, a symmetrical dual power supply with constant voltage outputs will be designed. A symmetrical dual power supply can provide two symmetrical voltages at the output with opposite polarity with respect to a common ground reference.Every electronic circuit needs a proper power supply at the input for its optimum functioning. The power supply of any device or circuit should be chosen as per its power requirements. In this project, a regulated power supply circuit which can output constant voltages of 9V and -9V with 1A maximum current is designed.
Protecting circuits from over current is an important aspect of circuit designing. The cause for over current can be intolerable voltage fluctuation in the power supply, short circuiting, failure of a device or component and overloading. Usually, for the protection of circuits from over current and so the damage from overheating of components, electronic fuses are used in their power supply sections. Electronic fuses are thin metallic wires which melt down over the passage of a threshold current. In the design of power circuits, apart from electronic fuses, circuit breakers are also used for circuit protection. Any circuit breaker operates like a relay which has the ability to detect a threshold current level and disconnect the rest of the circuit by tripping off the supplies.
Audio is one of the most common media. Here, It refers to the representation of sound which can be perceived by humans. Audio and Video are the essential component of any electronic media. The electronics can be used to receive audio signals (via microphone), record audio in some storage, transmit audio (through wired or wireless communication channels) and reproduce audio signals (via speakers). The audio can be represented and transmitted as either analog signals or digital signals. In this series, analog audio signals are the concern. The audio signals have a frequency range of 20 Hz to 20,000 Hz.
In the previous tutorial, a Bass Boost Power Amplifier was designed. Now it’s time to start designing power amplifiers suitable for specific applications. In this tutorial, a car audio amplifier will be designed. The cars have been coming with inbuilt audio systems from years. An audio system of a car is one of the important features that shines as unique selling point (USP) for any car in the market. The audio systems have become a vital accessory for any car. Even many times consumers replace the default audio systems came in their car with new one for better driving experience.
Continuing with the designing of application specific power amplifiers, in this tutorial a low power amplifier will be designed for regular mobile headphones. In the previous tutorial, a car audio amplifier using TDA2003 IC was designed. The mobile headphones are a type of miniature speakers designed especially for use with smart phones. These headphones do not have louder sound output. However, their sound quality can be improved by using an amplifier circuit with them. For headphones, a low power amplifier need to be designed.
Everyone must be familiar with the term – Switched Mode Power Supply or SMPS. Yes, they are used in every personal computer. In fact, the Switched Mode Power Supply is widely used with many other devices. Once it is understood that what SMPS actually is, its countless applications can be easily imagined. An SMPS is used for converting the electronic power supply efficiently. Any SMPS has some storage components which store electrical energy to supply to the load device and some switching components which turn on and off at high frequencies charging and discharging the storage components.
In the previous tutorial, fundamentals of audio filters were discussed. The audio filters can be passive or active depending upon the use of passive or active components in their designing. On the basis of frequency response, filters can be classified as high pass, low pass, band pass, Notch, band reject, T-Notch, all pass and equalizer filters. In this tutorial, an audio crossover will be designed. The Audio crossover is an electronics circuit which splits the audio signal into two or more frequency bands. These frequency bands are then, sent to the different audio drivers (Twitters, Mid Range and Woofers). A single speaker is not capable to serve the whole range of audible frequencies due to the limitations of its construction. So, different drivers (speakers) are required to deliver different range of audio frequencies.
The audio electronics is a branch of electronics that deals with designing of circuits that convert sound into electrical signals or electrical signals back into the sound. These circuits all together form an audio system. Basically, an audio system is designed to receive audio signals (via microphone), record audio in some storage, transmit audio (through wired or wireless communication channels) and reproduce audio signals (via speakers). So, the audio circuits perform signal processing for representing the sound in the form of electrical signals, manipulate the electrical (audio) signals like amplifying, filtering or mixing, reproduce sound from the audio signals, store audio into computer files or reproduce audio from an audio file. All these processes are performed by different audio related circuits or devices.
In the previous tutorial, sound wave and its properties were discussed. Now it’s time to understand Acoustic Waves. Generally, the term sound wave is used to refer the waves having frequency range audible to humans that is 20 Hz to 20 KHz. The waves having frequency greater than 20 KHz are called Ultrasonic waves and waves having a frequency range in Giga Hertz or higher are called Hypersonic Waves.
In the previous tutorials, physical properties of sound waves and acoustic waves were discussed. Sound or Acoustic Waves are in the form of vibration. Sound needs to be converted into electrical signals so that it can be processed by electronic circuits. So, the sound which is a mechanical energy must convert into electrical energy and must be precisely represented as an electrical waveform (analog) for any signal processing operations. So, there is need of a device which could sense the audio signals efficiently and convert them into electrical signals.