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Voltage Regulator Circuits

Voltage Regulators:  #'s - A       B - D       E - K       L - Q       P - S      
T - Z

 

Last Updated: 09/06/2020 02:31 PM



Circuits Designed by Dave Johnson, P.E. :

Laptop Power Supply -  Concept Only.  I have a big screen HP laptop computer.  The large brick size AC to DC power supply is rated at 19.2v and 9.5 amps, which is about 180 watts.  I'd like to be able to use the thing in my car.  I looked into a 12v car adapter for it but never really found one that I liked. . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2009

Light to Frequency Converter -  This circuit uses a CMOS version of the classic 555 timer, to form a light intensity to frequency converter.  A small Pin photo diode is used as the light detector.  The pulses produced are short, so in some applications you may want to stretch them or . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2008

LM317 adjustable voltage regulator used in Battery Eliminator Circuit -  if you use a 1.5v or a 3v battery powered MP3 player for long periods of time, you may get tired of constantly changing batteries.  Some older players do not work will NiMH rechargeable batteries so changing out batteries can get expensive.  The circuit be . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2005

Miniature Pushbutton On/Off Switch -  in many battery powered devices, you would like to turn the circuit on and off by pressing a small pushbutton switch.  One press turns the device on and second press turns it back off.  The flip/flop circuit below uses a minimum number of parts to perform . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2005

Negative 0.5 Volt Supply -  This simple circuit consists of two LEDs and a photo diode.  it generates a negative voltage with a current level of a couple milliamps.  it is ideal for supplying a negative rail to low power “rail to rail” op amp circuits, which need to have a true zero volts output.  Note:  This circuit is not particularly efficient . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

Nine-Volt Battery Eliminator -  if you use 9v battery powered devices for long periods of time, you may get tired of constantly changing batteries.  The circuit below can be wired into any 9v battery powered device, drawing power from an external AC to DC power adapter.  I designed the circuit. . . Circuit by David A. Johnson P.E.-December, 2009

Capacitance Proximity Switch
Draws very low power - Ideal for battery-powered applications
6 Models Available - Call 806-778-8210




Links to electronic circuits, electronic schematics and designs for engineers, hobbyists, students & inventors:

L200 Power Supply -  Power supply with variable voltage and fixed current regulation made using the ubiquitous L200C regulator.   __ Designed by Andy Collison

Lantern Flasher/Dimmer -  Basically a high-efficiency dimmer, but can also be used as a flasher.  in dimmer mode, the LM358 (dual op-amp) is wired to send pulses at a constant frequency.  By adjusting the width of these pulses, brightness of the bulb is controlled.  in flasher mode, the same potentiometer is used to control the frequency, from about 1 to 20 flashes per second__ tomzi.geo page

Lantern Flasher/Dimmer -  The electronic lantern control circuit (fig.1) adds high-efficiency dimming and flashing to an existing battery-powered lantern or flashlight or to a custom design.  For the car it makes a great lamp for changing a flat tire, back seat reading or emergency engine work.  The flasher mode is useful for warning other drivers __  Contact:  Charles Wenzel of Wenzel Associates, Inc.

Lantern Flasher/Dimmer -  The electronic lantern control circuit adds high-efficiency dimming and flashing to an existing battery-powered lantern or flashlight or to a custom design.  For the car it makes a great lamp for changing a flat tire, back seat reading or emergency engine work.  The flasher mode __ Designed by Tony van Roon  VA3AVR

Laptop Power Supply -  Concept Only.  I have a big screen HP laptop computer.  The large brick size AC to DC power supply is rated at 19.2v and 9.5 amps, which is about 180 watts.  I'd like to be able to use the thing in my car.  I looked into a 12v car adapter for it but never really found one that I liked. . . . Hobby Circuit designed by Dave Johnson P.E.-July, 2009

Last-Gasp 5V Output from 12V to 15V Supply using a Supercapacitor -  The LT3009 is a micropower low dropout voltage (LDO) linear regulators that supplies 20mA output current with a dropout voltage of 300mV.  __ Linear Technology/Analog Devices App Note, Mar 24th 2010

Latching Regulator Prevents Deep Discharge -  03/16/95 EDN Design Ideas:  To avoid a deep discharge that can shorten or destroy a rechargeable battery's life, you need to remove the load at the point of complete discharge.  Because a battery's terminal voltage recovers after load removal, you can't simply disconnect the load when the voltage dips below a threshold and reconnect it when the voltage returns above that threshold Design by Doug Vargha, Maxim Integrated Products, Sunnyvale, CA

LCD Bias (+5V,-7.5V, +12.5V) Plus 8 LED Power Supply -  The LTC3524 is an integrated Bias and white LED power converter solution for small/medium-sized polysilicon thin film transistor (TFT) liquid crystal (LCD) display panels.  A 1.5MHz synchronous boost converter generates a programmable low noise, high efficiency 25mA TFT supply of up to 6.0V.  Regulated, low ripple charge pumps are used to generate up to +20V and –20V at 2mA.  A second 1.5MHz boost converter powers one or two LED strings with up to five series elements each__ Linear Technology/Analog Devices App Note, May 24, 2010

LDO Provides Smart Power Monitoring -  10/24/96 EDN Design Ideas:  Modern low-dropout (LDO) voltage regulators for battery-powered or other micropower applications offer a variety of monitoring and diagnostic functions, such as low-battery and out-of-regulation signals.  Dedicated LED indicators for these diagnostic functions, plus a typical power-on indicator, consume relatively large amounts of power.  This design integrates several power-monitoring/diagnostic functions into one bicolor LED, thus conserving power and extending battery life.  The smart power monitor in Figure 1 exploits the visual attributes, including continuous glow, blinking, and color variance, of the bicolor LED to display the normal operating condition and the low-battery and out-of-regulation conditions.   Design by Alexander Belousov, Consultant, Rego Park, NY

Leakage-energy recuperating winding self-supplies a DC-DC converter -  EDN Design Ideas:  07/05/2013    Use a bifilar winding as a snubber to clamp ringing and power the PWM controller IC  Design by Todor Arsenov

LED current regulator has low dropout -  EDN Design Ideas:  05/24/2016    Meet an interesting addition to the field of LED current regulators Design by Peter Demchenko

Light Bulb Voltage Regulator  -  The LVR2 and LVR3 work by Pulse Width Modulating the battery voltage and applying that to the light bulb.  in simpler terms it turns the light on and off so fast that the bulb appears to burn smoothly.  The LVR adjusts the time on versus the time off precisely, so that can the bulb maintains the same brightness even as the battery voltage drops, until the battery voltage is the same as the bulb voltage.  At that point the LVR is on 100% of the time and the bulb grows dimmer with further battery drop. __ Designed by Willie Hunt

Light to Frequency Converter -  This circuit uses a CMOS version of the classic 555 timer, to form a light intensity to frequency converter.  A small Pin photo diode is used as the light detector.  The pulses produced are short, so in some applications you may want to stretch them or . . . Hobby Circuit designed by David A. Johnson P.E.-May, 2008

Limits DV/DTand Capacitor inrush at Regulator Turn On -  10/11/07 EDN Design Ideas:  Adding a simple circuit to the adjust pin of a regulator controls the dV/dt of the output voltage, limiting inrush current Design by W Stephen Woodward, Chapel Hill, NC

Line Power Supply -  This circuit provides a regulated output without a power transformer.  it is similar to common circuits, except that a zener diode is replaced with an SCR.    This is far more robust against line voltages surges than a zener diode version, plus there is no h __ Designed by Andrew R. Morris

Linear & Switching Voltage Regulator Fundamentals -  Great article, thanks to Bryan for finding this one.  PDF format.  __ 

Linear Regulator Converts 3.3 to 2.9V -  03/16/95 EDN Design Ideas:  A linear regulator is often a better choice for developing supply voltages below 3.3 V than a switching regulator.  At low output voltages and moderate currents, the linear regulator is less expensive and requires less pc-board are Design by Matt Schindler, Maxim Integrated Products, Sunnyvale, CA

Linear regulator=low-cost DC/DC converter -  03/16/95 EDN Design Ideas:  A linear regulator is often a better choice for developing supply voltages below 3.3 V than a switching regulator.  At low output voltages and moderate currents, the linear regulator is less expensive and requires less pc-board are Design by Susanne Nell, Breitenfurt, Austria

linear voltage regulator with ultra Low drop -  The circuit is a MOSFET based linear voltage regulator with a voltage drop of as low as 60 mV at 1 ampere.  Drop of a fewer millivolts is possible with better MOSFETs having lower RDS (on) resistance.  The circuit in Fig.1 uses 15V-0-15V secondary __ Designed by Radio LocMan

LM2940 12V 1A Low Dropout Regulator -  Find out how to use an LM2940 to efficiently regulate voltage.   __ Designed by REUK-Renewable Energy UK website

LM2941 1A Low Dropout Adjustable Regulator -  Find out about the LM2941 - an adjustable regulator with very low dropout voltage.   __ Designed by REUK-Renewable Energy UK website

LM317 adjustable voltage regulator used in Battery Eliminator Circuit -  if you use a 1.5v or a 3v battery powered MP3 player for long periods of time, you may get tired of constantly changing batteries.  Some older players do not work will NiMH rechargeable batteries so changing out batteries can get expensive.  The circuit be . . . Hobby Circuit designed by David A. Johnson P.E.-June, 2005

LM317 Current Calculator -  A handy online output current calculator for the LM317, LM338, and other linear voltage regulators.   __ Designed by REUK-Renewable Energy UK website

LM317 High Current Voltage Regulator -  Find out how to build an LM317T based high current voltage regulator.   __ Designed by REUK-Renewable Energy UK website

LM317 Regulator -  I constructed this voltage regulator to power my two way mobile radio from the car cigarette lighter circuit.  it has many other uses and the voltage can easily be adjusted by the use of a potentiometer.  The voltage regulator is an LM317T, and should accept up to about 14 volts without problems.  it can handle up to 1 amp, but you WiLL need a heatsink on the voltage regulator __ Designed by Matthew Hewson

LM317 Regulator with Pass Transistor -  The LM317T output current can be increased by using an additional power transistor to share a portion of the total current.  The amount of current sharing is established with a resistor placed in series with the 317 input and a resistor placed in series with the emitter of the pass transistor.  in the figure below, the pass transistor will start conducting when the LM317 current reaches about 1 amp, due to the voltage drop across the 0.7 ohm resistor __ Designed by Bill Bowden

LM317 smooths but doesn't regulate -  EDN Design Ideas:  06/03/2016    I once needed to clean up a power supply output, but it didn't need to be regulated.   A well known power supply circuit is the capacitance multiplier.  it doesn't regulate, but instead reduces ripple & noise while the output tracks at some fraction of the input voltage.   The R1/R2 voltage divider determines VOUT (a VBE below VB) , and must be chosen to account for the maximum ripple on the minimum ViN.   if ViN is regulated, the circuit can be used purely for low-level noise reduction.  in this case, only one resistor is needed if you want to minimize the drop. Design by Michael Dunn

LM317 used as 0 to 3V Adjustable Regulator -  10/02/08  EDN Design Ideas:  LM317 acts as an adjustable regulator Design by Vladimir Rentyuk, Modul-98 Ltd, Zaporozhye, Ukraine

LM317 Variable Voltage Regulator -  The LM317T is a adjustable 3 terminal positive voltage regulator capable of supplying in excess of 1.5 amps over an output range of 1.25 to 37 volts.  The device also has built in current limiting and thermal shutdown which makes it essentially blow-out proof __ Designed by Bill Bowden

LM317 Voltage Calculator -  A handy online output voltage calculator for the LM317, LM338, and other linear voltage regulators.   __ Designed by REUK-Renewable Energy UK website

LM317T Heatsinking -  Choosing a heatsink for use with an LM317T voltage regulator.   __ Designed by REUK-Renewable Energy UK website

LM317T Voltage Regulator Chip -  Learn about the LM317T and its uses in renewable energy projects.   __ Designed by REUK-Renewable Energy UK website

LM723 Power Supply Voltage & Current Regulated -  A Versatile and Most useful device, Especially for the Beginner __ Designed by G.L. Chemelec   

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Voltage Regulators:  #'s - A       B - D       E - K       L - Q       P - S       T - Z


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