Discrete Transistor Voltage Regulators

john July 2, 2014 No Comments
Basically there are two types of transistor voltage regulators. They are (i) Series Voltage Regulators and (ii) Shunt Voltage Regulators. Each type of circuit can provide an output dc voltage that is regulated or maintained at a predetermined value even if the input voltage varies or the load connected to the output terminal changes. You may also go through the following articles: Regulated Power Supply,Voltage Regulators, Zener Controlled Transistor Voltage Regulators, and IC Voltage Regulators Series Voltage Regulator The basic connection...
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Voltage regulator

Voltage Regulators

john August 9, 2018 5 Comments
A voltage regulator is designed to automatically ‘regulate’ voltage level. It basically steps down the input voltage to the desired level and keeps that in that same level during the supply. This makes sure that even when a load is applied the voltage doesn’t drop. Thus, a voltage regulator is used for two reasons:- To regulate or vary the output voltage of the circuit. To keep the output voltage constant at the desired value in-spite of variations in the...
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Regulated power supply

Regulated Power Supply

john August 13, 2018 21 Comments
INTRODUCTION Almost all basic household electronic circuits need an unregulated AC to be converted to constant DC, in order to operate the electronic device. All devices will have a certain power supply limit and the electronic circuits inside these devices must be able to supply a constant DC voltage within this limit. This DC supply is regulated and limited in terms of voltage and current. But the supply provided from mains may be fluctuating and could easily break down...
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Positive voltage to negative voltage converter

john February 28, 2010 6 Comments
Description. This circuit diagram shows how to obtain a negative voltage from a positive voltage supply. Another advantage of this circuit is that, the negative voltage together with the original positive supply can be used to simulate a dual supply. The circuit is based on timer IC NE555. The NE555 is wired as an astable multivibrator operating at around 1 KHz. The square wave output if available at pin no 3 of the IC. During the positive half of...
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5V transformer less power supply

john January 8, 2011 13 Comments
Description. Here is the circuit diagram of a 5V transformer less power supply using minimum components. The working of this circuit is quite simple. Resistor R1 does the job of current limiting and bridge D1 rectifies the mains voltage. The Zener diode regulates the rectifier output to obtain a steady 5V DC and capacitor C2 acts as a filter. Circuit diagram. Notes. Assemble the circuit on a Vero board. The circuit is directly connected to the mains supply, be...
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Variable power supply using 7805

john September 17, 2009 8 Comments
Description. This circuit diagram shows you how to make a 5V to 12V variable DC power supply from a fixed 5V regulator IC 7805. This is attained by adding two resistors R1 and R2 as shown in figure. When the resistors R1 and R2 are added the equation for the output voltage of 7805 becomes  Vout= Vfixed + { R2 } ,where Vfixed=5V and Istandby=Vfixed/R1.By varying the POT R2 you can adjust the output...
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Polyphase rectifiers

jojo December 19, 2013 No Comments
Polyphase rectifier In polyphase rectifier we will be discussing in detail the working, the input and the output wave forms of a three phase half wave rectifier and three phase full wave rectifier, along with the connections of an interface transformer on a 6-diode rectifier. Three phase Half Wave Rectifier A three phase half wave rectifier, as the name implies , consists of a three phase transformer. Given below is a star connected secondary three phase transformer with three...
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Full wave bridge rectifier

jojo July 31, 2018 25 Comments
A Full wave rectifier is a circuit arrangement which makes use of both half cycles of input alternating current (AC) and converts them to direct current (DC). In our tutorial on Half wave rectifiers, we have seen that a half wave rectifier makes use of only one-half cycle of the input alternating current. Thus a full wave rectifier is much more efficient (double+) than a half wave rectifier. This process of converting both half cycles of the input supply...
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Centre-Tap Full-Wave Rectifier

jojo December 19, 2013 2 Comments
Centre-Tap Full Wave Rectifier We have already discussed the Full Wave Bridge Rectifier, which uses four diodes, arranged as a bridge, to convert the input alternating current (AC) in both half cycles to direct current (DC). In the case of centre-tap full wave rectifier, only two diodes are used, and are connected to the opposite ends of a centre-tapped secondary transformer as shown in the figure below. The centre-tap is usually considered as the ground point or the zero...
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Half wave rectifiers

jojo July 31, 2018 55 Comments
A simple Half Wave Rectifier is nothing more than a single pn junction diode connected in series to the load resistor. As you know a diode is to electric current like a one-way valve is to water, it allows electric current to flow in only one direction. This property of the diode is very useful in creating simple rectifiers which are used to convert AC to DC. If you look at the above diagram, we are giving an alternating...
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