General information on low voltage linear power supplies
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• Theory

• A Designer's Guide to the L200 Voltage Regulator -   
• Change improves regulators reliability - standard circuit for adjustable, 3-terminal regulators (LM317, LM350, etc) suffers from a designed-in fault: If the potentiometer R2s wiper loses contact, the regulators output goes high   
• DMOS delivers dramatic performance gains to LDO regulators - LDO regulators with pnp pass elements nearly obsoleted the early npn linear regulators   
• Emitter-Follower Boosts Linear Regulator's Output Current - an external emitter-follower increases the output current while maintaining the low quiescent current of this LDO regulator   
• Extend the input range of a low-dropout regulator - Because of process limitations, all ICs have an input-voltage limitation. This limitation can be cumbersome when you try to step down a high supply voltage to a lower, regulated voltage using a dc/dc converter, such as a linear regulator. Adding a FET to the input of a linear regulator creates a dc/dc converter with a wider input-voltage range than the range of the regulator alone. The excess voltage and, therefore, power occurs in the FET.   
• Full Wave Rectification - This article describes how full wave rectification using four diodes works.   
• Full-wave DC power supply - This is a simulation of a simple DC power supply based on a full-wave rectifier. This power supply uses center-tapped transformer and two diodes. This type of circuit is also known as a biphase rectifier.   
• Increasing Regulator Current - Although the 78xx series of voltage regulators are available with different current outputs, you can boost the available current output with this circuit. A power transistor is used to supply extra current to the load the regulator, maintaining a constant voltage.   
• Inside a Power-Cube Transformer - How those little things convert mains AC to safe low voltage DC   
• Increasing Regulator Current - you can boost the available current output of 78xx series of voltage regulators with this circuit   
• Keep linear regulators in their safe zone - thermal characteristics of regulators depend on their operating conditions and the system's load   
• Method of Determining Secondary Current Ratings in D.C. Circuits - This document gives you the equations for Half Wave Rectifier (HWR), Full Wave Center Tap (FWCT), Full Wave Bridge (FWB) and Dual Complementary Rectifies (DCR). Also example circuits are given. This document gives also information how to add a regulator to the power supply output.   
• Power supplies - theory   
• Rectifier Applications Handbook   
• Transformer Facts Technical Bulletin No.1: Application Notes on Rectifier Transformers  
• Understanding linear regulators - Linear regulators convert unregulated dc voltage to regulated dc voltage. are good vehicles to use to begin a voltage-regulator study.   
• Unregulated Power Supply - sample circuits and some information which describes it's operation and calculation of component values   
• Unregulated power supply design   
• Voltage regulators (stabilizers) 78xx a 79xx by ST - warning about some possible problem if the regulator load is too low   
• Zener Voltage Regulator CALCULATOR   
   

• Unregulated power supplies

• 12V DC Power Supply - uses 12V 5A transformer and some basic components to give put unregulated +12V   
• Method of Determining Secondary Current Ratings in D.C. Circuits - This document gives you the equations for Half Wave Rectifier (HWR), Full Wave Center Tap (FWCT), Full Wave Bridge (FWB) and Dual Complementary Rectifies (DCR). Also example circuits are given. This document gives also information how to add a regulator to the power supply output.   
• Dual Unregulated Power Supply for Audio Power Amplifiers - This kit is a quick, neat, and inexpensive way to provide a smoothed dual unregulated DC power supply suitable for powering many audio power amplifiers.   
• Half-wave DC power supply - This is a simulation of a simple DC power supply based on a half-wave rectifier.   
• Ian Purdie's Amateur Radio Tutorial Pages: Your Basic Power Supply Circuit - This is the circuit of a basic unregulated dc power supply.   
• Power Supply for Battery Valve Radios - to make 90V DC and 1.5V DC for 7-pin valves used in old radios   
• Reusing that Wall Wart, Revisited - This article gives ideas on how to decide to either reuse the unregulated Wall Wart as it is, or not.   
• Unregulated Power Supply - basic operation described, useful general circuit for many different voltages   
   

• Fixed voltage regulated

• 12 Volt 30 Amp Power Supply - This circuit uses a single 7812 IC voltage regulator and multiple outboard pass transistors (TIP2955). This power supply can deliver output load currents of up to 30 amps.   
• 12V RMS to 10V Voltage Regulator - will take a 12V RMS sinusoidal input from a transformer and provide a 10V DC output at 100 mA with very good regulation   
• 12 Volt to 9 Volt DC Converter   
• 13.8V 20A power supply - Regulated DC power supply, short circuit safe, and with current limiter. This PSU has been especially designed for current-hungry ham radio transceivers. It delivers safely around 20Amps at 13.8V. For lower currents, a separate current limiting output, capable of 15ma up to a total of 20A has been added. The base of this design is a simple 12V regulator (7812) and power transistors.   
• 48 Volt Phantom Power Supply - This is a simple 48 V regulated linear power supply design that will provide up to 60 mA of current. This circuit is based on the Texas Instruments TL783C high voltage adjustable linear regulator IC. This circuit is short circuit protected.   
• 78xx regulator board - circuit board and ccircuit for making voltage regulators based on 78xx ICs, in pdf format, text in Finnish   
• A constant 5 volts DC power supply - This is an example of a power supply to power anything requiring 5 volts DC. This circuit takes low voltage AC in (9-16V AC).   
• Active preloading provides sinking capability - a simple add-on circuit enables a unipolar power supply, usually a current-sourcing circuit only, to sink current from a load   
• Circuit reduces VCC ripple in audio band - regulator circuit which reduces noise and ripple by at least 35 dB over the audio range of 100 Hz to 20 kHz and provides a clean source of 5V power for driving audio circuits in portable applications such as cellular phones and multimedia notebook computers   
• DC power supply - simple circuit based on 78xx fixed voltage regulator IC, those ICs are available for some fixed voltages between 5 and 24V   
• Discrete LDO Regulator - The discrete LDO design presented here came about because of the need for an LDO (low drop-out regulator) for 5V designs. There are better performing LDO parts, but they tend to be either single sourced or expensive. This one can be made from common components. The performance parameters are very crude : 5V nominal at up to 10mA from 6-16V.   
• Explanamtion and experiment about regulated DC power supply - many power supply designs for different voltages, built from discrete components   
• Increasing Regulator Current - you can boost 78xx regulator output with one power transistor   
• Linear supply uses switch-mode regulation - You can use simple circuits to implement small, regulated plug-in power supplies. This basic and versatile 5V supply uses a zener diode and an emitter-follower transistor.   
• Logic PSU with Over Voltage Protection - 5 volt regulated power supply for TTL and 74LS series integrated circuits, includes output overvoltage fault protection   
• Low-drop regulator - outputs 5V at 1A, constructed from discrete components, in postscript file format   
• MOSFET circuit ups regulator's output current - use a current mirror and a power MOSFET to increase the output-current capability of an IC-voltage regulator   
• Power Supply for Preamplifiers - gives +/-15V outputs and takes power from external AC power supply   
• Regulated 12 Supply - provides a regulated 12 volts at 0.5 amp to a load, built from discrete components   
• Regulated 12 Volts DC Power Supply for Vacuum Tube Heaters - this 7812 based circuit circuit can be used with low-hum audio applications such as microphone preamps and for other applications that require well regulated 12 volts   
• Regulator excels in noise and line rejection - certain electronic circuits require extremely low-noise power supplies and this circuit provides very good quality power output   
• Regulator generates sub-bandgap voltages - 100-mA regulator that uses a dual linear-regulator IC to produce output voltages below 1.25V from 2.9 to 5.5V input-voltage range   
• Sam's Schematic Collection of various circuits - includes many regulated power supply circuits   
• Simple 5V power supply for digital circuits    Rate this link
• The Spyder - an Eight-Output Pedalboard Power Supply - outputs regulated 9V DC   
• Universal DC-DC Convertor - This circuit will generate a smaller DC output voltage from a larger DC input voltage.It is quick and simple to make and by changing the value of the zener diode, the circuit can be universally adapted to provide other output voltages. The circuit and all diagrams represent a DC convertor with 12V battery input and 9Volt DC output.   
• Voltage Regulator - simple regulated 12V power supply using one transistor regulator circuit   
• Zener Diode Calculator - This calculator is designed to give the wattage and resistance of the circuit power resistor, the voltage and wattage rating of the Zener diode and general design schematic for the circuit. Enter the maximum and minimum voltage inputs; enter the voltage output and the anticipated current rating. Click on Calculate and the results will be displayed.   
   

• Adjustable regulated power supplies

• 0-30 VDC Stabilized Power Supply With Current Control 0.002-3A - This is a high quality power supply with a continuously variable stabilised output adjustable at any value between 0 and 30VDC. The circuit also incorporates an electronic output current limiter that effectively controls the output current from a few milliamperes (2 mA) to the maximum output of three amperes that the circuit can deliver. This feature makes this power supply indispensable in the experimenters laboratory as it is possible to limit the current to the typical maximum that a circuit under test may require, and power it up then, without any fear that it may be damaged if something goes wrong. There is also a visual indication that the current limiter is in operation so that you can see at a glance that your circuit is exceeding or not its preset limits.   
• 0-30 Volt Laboratory Power Supply - This circuit provides 0-30 volts, at 1 amp, maximum, using a discrete transistor regulator with op-amp feedback to control the output voltage. This power supply has constant current mode suitable for charging batteries.   
• 0 - 300V Adjustable Power suppy - This is a simple circuit which can provide an adjustable voltage source of 0 to 330 Volt. The supply is short-ciruit proof: the current is limited to about 100mA.   
• 10 amp Power Supply - This is a simple regulated power supply that can give adjustable voltage from 3 volts to 18 volts. The current capacity is 10 amperes. This circuit is overcurrent protected. This circuit can be modified for higher current ratings if needed.   
• 1.2-25VDC at 4A power supply schematic - built using discrete transistors and 741 opamp, read   
• 1A Variabe Power Supply - This circuit takes in 240V AC and outputs a regulated DC at voltage sange of 2-15V DC up to 1.5A.   
• Adjustable power supply using LM317 - voltage regulator for 1.2V to 35V output voltages and up to 1A load   
• Build a Variable Voltage Supply for Cheap - This is a variable voltage 1.5A supply that can be built cheaply and used for bench experimeting. With a 24VDC wall wart, this board can produce anywhere from 23V to 1.2V   
• High Current Regulated Supply - uses pair of 3N3055 transistors to give out currents up to 15A   
• L200 Regulator Circuit - easy to build a power supply with one single L200 IC, offers a variable current limit of up to 2 A, as well as voltage regulation   
• Variable 3 - 24 Volt / 3 Amp Power Supply - regulated power supply can be adjusted from 3 to 25 volts and is current limited   
• S��dett�v� j�nnitel�hde 0-24V 4A - 0-24V 4A adjustable power supply, text in Finnish   
• Variable Power Supply - based on versatile L200 voltage regulator, independent voltage (3-15V) and current (10mA-2A) limits   
• Variable Regulated Power Supply - This is a simple, but low-ripple powersupply, and an excellent project if you're starting out in electronics. It will suit your needs for most of your bench testing and prototype applications. The output is adjustable from 1.2 volts to about 30 volts. Maximum current is about 1.5 amp.   
   

• Dual polarity power supplies

• Dual +/-15 Volt Power Supply - suitable for powering opamp circuits   
• Electronic Regulated Power Supplies - low noise +-62V regulated power supply for audio applications with PSRR up into 80dB   
• Op amp makes precise 9V-battery splitter - alkaline 9V batteries are ideal for many portable, handheld applications, this circuit generates a bipolar supply of 5V and �2.3 to �4V using a precision 5V reference and one op amp as a supply splitter   
• Power Supply for Preamplifiers - low noise regulated +/-15V power supply   
• Renkus-Heinz Controller Power Supply - outputs regulated +-15V   
• Simple DC Adapter Power Supply - DC voltage "virtual earth" circuits   
• Variable Dual Lab Power Supply - can supply from +/-1.2V up to about +/-25V, will current limit at around 800mA   
   

• Negative voltage generating circuits

• Generating -5VDC from +5VDC - simple capacitor pump circuit based on 555 chip   
• Generating -5 Volts From a 9 Volt Battery   
   

• CD player adaptors

• Walkman 3V Power Supply   
   

• Misc circuits

• Circuit provides hiccup-current limiting - Current-limit protection is an essential feature for power-supply systems. The three major types of current-limit-protection mechanisms are constant, foldback, and hiccup. Hiccup current limit performs the best of the three types; however, the implementation is rather complex.   
• High-Current, Low-Voltage Shunt Regulator - up to 8 A shunt-regulator built around the TLV431 low-voltage, adjustable, precision shunt-regulator IC   
• Take power out of PC RS-232 port   
• Power supplies and transformers - basic structures of power supplies   

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