Dual Power Supply using LM 320 and LM 340 Bipolar or dual voltage supplies can be easily designed with the help of two 3-terminal regulators. This is shown in the figure above using the IC’s LM320 and LM 340. Opposite-phase ac is provided by the transformer’s secondary and a grounded center tap. The single full-wave […]
A voltage regulator is one of the most widely used electronic circuitry in any device. A regulated voltage (without fluctuations & noise levels) is very important for the smooth functioning of many digital electronic devices. A common case is with micro controllers, where a smooth regulated input voltage must be supplied for the micro controller
If the load resistance RL is reduced or load terminals are shorted accidenÂtally, a very large load current will flow. It may destroy the pass transistor Q1, diode or possibly some other component. Fuse protection will not prove adequate because the transistor may get damaged in a very small fraction of a second To avoid
Controlled Transistor Series Regulator A controlled transistor series regulaÂtor is shown in the figure. The circuit is quite similar to that of a simple transistor series voltage regulator except that an additional transistor Q2 is inserted in the circuit. The emitter terminal of this transistor Q2 is connected to the negative terminal of input supply
The efficiency of Zener regulated power supply becomes very low when the load current is high. Under such conditions a Zener controlled transistor is always used for maintaining output voltage constant. Basically there are two types of Zener controlled transistor voltage regulators. They are Series Voltage Regulators Shunt Voltage Regulators You may also go through
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
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
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
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
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
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 becomesÂ
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
A Full-wave rectifier is a circuit arrangement that 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
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
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
General Introduction to DC power supplies: The electrical power is almost exclusively generated, transmitted and distributed in the form of ac because of economical consideration but for operation of most of the electronic devices and circuits, dc supply is required. Dry cells and batteries can be used for this purpose. No doubt, they have the
Description. This dual power supply is based on the L165 power operational amplifier from SGS-Thomson Micro electronics. The IC L165 can easily deliver up to 3.5A of current (internally limited). The IC is available in Pentawatt package and is very suitable for power supply applications like this. Here the L165 is wired as a voltage
Description. This 13V/5A power supply is based on the famous LM338 IC from the ST Microelectronics. The IC has time dependent current limiting, thermal regulation and is available in 3 lead transistor package. The IC can easily supply well over 5A at an output voltage range between 1.2V and 30V. In this circuit the output
Description. This is the circuit diagram of a 3A adjustable power supply using IC LM350K.. LM350K is a very rugged voltage regulator IC with features like thermal regulation, short circuit protection etc. This circuit is designed as per the application notes in the data sheet and was found to be working very fine.This circuit has
Description. Here is the circuit diagram of a fuse that has an automatic status indicator. This circuit can be added to circuit that operates from 12V DC. As long as the fuse is intact, the LED D3 will glow continuously and when the fuse blows off the LED will start and continue blinking. The first
Description. This 40V dual power supply circuit was designed in response to a request made by Michael from Philippines. His application is to power the 150 Watt amplifier circuit published here. I think this power supply design is adequate for the purpose. The transformer T1 steps down the mains voltage, bridge D1 performs the rectification,
Description. The circuit given below is of a simple audio amplifier that can deliver 12W to an 8 Ohm speaker. Op amp IC TL081 is used as the preamplifier here. Actually any opamp with matching power supply ratings can be used instead of TL081.Transistors Q1 and Q2 (TIP125 and TIP120) comprises the power amplifier stage.
Dual Power Supply Circuit Description The circuit given here is of a regulated dual power supply that provides +12V and -12V from the AC mains. A power supply like this is a very essential tool on the work bench of an electronic hobbyist. The transformer T1 steps down the AC mains voltage and diodes D1,
Description. This 1.3V power supply can be used as replacement for the 1.3V Mercury Cell in any circuit. When the input 5V is given to the circuit, the voltage drop across zener diode D1 will be around 2V.The diode D2 will drop a 0.7 V from the 2V volt and the remaining 1.3V will be
Description. Here is the circuit diagram of a simple soft start power supply using the well known IC L200.The L200 is a monolithic IC that can be used for voltage and current regulation. The built-in features such as thermal shut down, over current protection and input over voltage protection makes this IC nearly indestructible. When
