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MicroPower  Circuits
Low Power (flea power): #'s - K        L - R        S - Z

Last Updated: June 02, 2021 01:44 PM

Circuits Designed by Dave Johnson, P.E. :

LED Flasher needs only 1.5 VOLTS - To squeeze even more energy from a alkaline battery cell, this circuit adds two transistors to a circuit similar to the above design to boost the efficiency.  A small 1.5 volt alkaline N cell should flash the LED for a full year.  It too uses a "charge pump" technique to provide a LED the needed voltage . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

LED Flasher that is Battery Free - LED flashers have been used for a wide variety of applications.  Some flasher units have been used in food and hardware stores, to draw attention to sale items and are often attached to boxes which dispense product discount coupons . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2010

LED Flasher-Wireless Circuit - When you would like to flash a LED through a thick plastic case without wires, use this hobby circuit.  It performs this feat.  It draws about 300ua of average current at 5v.  It can be powered from a supply ranging from 3v to 6v . . . Hobby Circuit designed by David Johnson P.E.-January, 2011

LED Flashing Badge #1 - I have seen numerous flashing light badges at trade shows and conventions.  They are often handed out as gifts to promote some business.  The devices often use inefficient circuits, which cause the battery power source to be quickly depleted. . . Circuit by David Johnson P.E.-March, 2002

LED Flashing Badge #2 - This circuit uses a CD4013 dual D Flip/Flop IC.  A single lithium battery will provide months of continuous LED flashing.  It also has a tiny push-button switch to turn on and off the light flashing. . . Circuit by David A. Johnson P.E.-March, 2002

Light Detector with High Ambient Light Immunity - This circuit is designed for detecting infrared light modulated at around 40KHz.  It’s feedback scheme cancels much of the DC component from ambient light.  It’s conversion factor is about 100 millivolts per microwatt of 900nm light.. . . Circuit by David Johnson P.E.-July, 2006

Light/Dark Activated Motion Detector - This circuit can sound an alarm when the shadow of a hand or arm moves over  two small photo diodes. . . Circuit by David Johnson P.E.-August, 2005

Line Status Indicator for 1 Telephone Line - This circuit monitors one phone line . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

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 Johnson P.E.-June, 2005


Links to electronic circuits, electronic schematics and designs for engineers, hobbyists, students & inventors:
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Latching light Detector is frugal with power & parts - 09/26/02 EDN-Design Ideas This idea demonstrates three uses for the humble LED.  The circuit in Figure 1a forms a simple light detector that latches and turns on an LED when the ambient light exceeds a preset limit determined by potentiometer P1.  LED D1 is both the indicator and the light detector.  All junction diodes exhibit some degree of photosensitivity Design by Anthony Smith, Scitech, Biddenham, Bedfordshire, UK

LED Flasher needs only 1.5 VOLTS - To squeeze even more energy from a alkaline battery cell, this circuit adds two transistors to a circuit similar to the above design to boost the efficiency.  A small 1.5 volt alkaline N cell should flash the LED for a full year.  It too uses a "charge pump" technique to provide a LED the needed voltage . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

LED Flasher that is Battery Free - LED flashers have been used for a wide variety of applications.  Some flasher units have been used in food and hardware stores, to draw attention to sale items and are often attached to boxes which dispense product discount coupons . . . Hobby Circuit designed by David A. Johnson P.E.-December, 2010

LED Flasher-Wireless Circuit - When you would like to flash a LED through a thick plastic case without wires, use this hobby circuit.  It performs this feat.  It draws about 300ua of average current at 5v.  It can be powered from a supply ranging from 3v to 6v . . . Hobby Circuit designed by David Johnson P.E.-January, 2011

LED Flashing Badge #1 - I have seen numerous flashing light badges at trade shows and conventions.  They are often handed out as gifts to promote some business.  The devices often use inefficient circuits, which cause the battery power source to be quickly depleted. . . Circuit by David Johnson P.E.-March, 2002

LED Flashing Badge #2 - This circuit uses a CD4013 dual D Flip/Flop IC.  A single lithium battery will provide months of continuous LED flashing.  It also has a tiny push-button switch to turn on and off the light flashing. . . Circuit by David A. Johnson P.E.-March, 2002

Light Detector with High Ambient Light Immunity - This circuit is designed for detecting infrared light modulated at around 40KHz.  It’s feedback scheme cancels much of the DC component from ambient light.  It’s conversion factor is about 100 millivolts per microwatt of 900nm light.. . . Circuit by David Johnson P.E.-July, 2006

Light/Dark Activated Motion Detector - This circuit can sound an alarm when the shadow of a hand or arm moves over  two small photo diodes. . . Circuit by David Johnson P.E.-August, 2005

Line Status Indicator for 1 Telephone Line - This circuit monitors one phone line . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

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 Johnson P.E.-June, 2005

Low Battery Voltage Flasher - This circuit is designed to monitor two alkaline cells  (3v) that form the battery often used in portable electronic equipment. . . Circuit by David Johnson P.E.-January, 1998

Low Frequency Oscillator draws only 2 Nanoamps - If you have hundreds of touch switches that need an excitation signal, then this circuit is what you need.  Its 20KHz 20v peak to peak output signal can supply up to 3 watts of touch switch excitation power. . . Circuit by Dave Johnson P.E.-July, 2006

Low Noise Micropower DC/DC Converters LT1500/LT1501 - DN151 Design Notes__ Linear Technology/Analog Devices

Low Power 40KHz Light Detector - This circuit is designed for detecting infrared light modulated at around 40KHz.  It’s feedback scheme cancels much of the DC component from ambient light.  It’s conversion factor is about 100 millivolts per microwatt of 900nm light.. . . Circuit by David A. Johnson P.E.-July, 2006

Low Power AM Transmitter - This "phono oscillator" design transmits over a suprising distance and uses only two valves.   __ Contact: blehack @ yahoo dot com

Low Power Audio Amp Experiments - The object of this experiment is to assemble and test a low-power audio amplifier that might be used to drive headphones.  Because an op amp is current limited to less than 25 mA, it cannot be used to directly drive a low impedance load.  A solution to this problem is to add current boosters between the op-amp output and the load as shown in Figure 1

Low Power Audio Amplifier Based on LM386 - Another super-simple circuit.  You could use this circuit to drive a low power speaker from a sound effects module or a noise generator.  Or you could build your own amplified speakers for use with your computer.   __ Designed by Bill's Electronics Reference Library

Low Power Blink LED - Schematic only, no circuit description __ Designed by Rob Crockett

Low Power CMOS RS485 Transceiver - DN39 Design Notes__ Linear Technology/Analog Devices

Low Power Comparator with <10uV Hysteresis - The opamp is used as a precision comparator that drives an NPN transistor to form a logic-level output.  Controlled positive feedback into a trim pin makes precision microvolt hysteresis control practical.  __ Linear Technology/Analog Devices App Note, Jun 21st 2011

Low Power DC-to-DC Converter - The circuit below is a DC to DC converter using a standard 12 VAC center tapped power transformer wired as a blocking oscillator.  The circuit is not very efficient but will produce a high voltage usable for low power applications.  The input battery voltage is raised by a factor of 10 across the transformer and further raised by a voltage tripler consisting of three capacitors and diodes connected to the high voltage side of the transformer __ Designed by Bill Bowden

Low Power Fast Op Amps Have Low Distortion - DN148 Design Notes__ Linear Technology/Analog Devices

Low Power FM Transmitter - Useful to retransmit the hi-fi to another FM receiver nearby, or as a wireless mic __ Designed by Rod Elliott  ESP

Low Power FM Transmitter - This low power fm transmitter is designed to use an input from another sound source and transmits on the commercial FM band.  This low power fm radio transmitter it is actually quite powerful.  The first stage is the oscillator, and is tuned with the variable capacitor.  Select an unused frequency, and carefully adjust C3 until the background noise is removed.

Low Power LED Flasher - Judging from the numerous references I have received, this electronic circuit, hobby circuit seems to be rather popular.  Many published circuits which flash LEDs need 3 or more volts.  This electronic circuit uses only a single inexpensive C-MOS IC and . . . Hobby Circuit designed by Dave Johnson P.E.-June, 2000

Low Power LED Flasher - It doesn't get much simpler than this circuit.  Four components counting the battery! How can an LED be illuminated by a 1.5V circuit, when the forward voltage of an LED is about 2V? The LM3909 uses the 100uF capacitor as a charge reservoir, building up a voltage of about 2V before discharging the cap through the LED. 

Low Power LED Voltmeter - This is a low power voltmeter circuit that can be used with alternative energy systems that run on 12 and 24 volt batteries.  The voltmeter is an expanded scale type that indicates small voltage steps over the 10 to 16 volt range for 12 volt batteries and over the 22 to 32 volt __ Designed by G. Forrest Cook

Low Power Op-Amp-Audio Amp Intercom - The example below illustrates using an op-amp as an audio amplifier for a simple intercom.  A small 8 ohm speaker is used as a microphone which is coupled to the op-amp input through a 0.1uF capacitor.  The speaker is sensitive to low frequencies and the small value capacitor serves to attenuate the lower tones and produce a better overall response.  You can experiment with different value capacitors to improve the response for various speakers.  The op-amp voltage gain is determined by the ratio of the feedback resistor to the series input resistor which is around one thousand in this case __ Designed by Bill Bowden

Low Power PLL FM Transmitter based on LMX1601 & Atmel ATtiny2313 or AT90S2313 microcontroller - An LMX1601 Phase locked loop, a discreetFET VCO, and an AVR micro controller combine to make a stable, easy to use monophonic FM transmitter that includes a an audio activated switch that turns the transmitter on only when its being used __ Designed by Dick Cappels

Low Power RFID Transponder - This is the Grand Prize winner in the design category of the 1993 RF Design Awards Contest.  This entry exhibited both innovative use of RF technology and an elegant implementation of that technology __ Designed by Raymond T. Page, Reprint courtesy of RF Design Magazine

Low Power Single-Ended 6SN7 Amp - I built this little amp for my computer at work.  It sounds pretty darn good thru some old speakers from an Emerson tube console.  At <1/2 Watt it is STILL too loud for my office.   __ Designed by Bob Danielak

Low power voltage-to-frequency converter makes a wireless probe for testing an inductive power supply - 26-May-05 EDN-Design Ideas Inductive pickup measures low-power circuit's supply Design by Francis Rodes, Eliane Garnier, and Salma Alozade, ENSEIRB Talence, France

Low Power, Bidirectional 60V Precision Hi Side Current Sense - Using a very precise zero-drift amplifier as a pre-amp allows for the use of a very small sense resistor in a high voltage supply line.  A floating power supply regulates the voltage across the pre-amplifier on any voltage rail up to the 60V limit of the LT1787HV circuit.  Overall gain of this circuit is 1000.  A 1mA change in __ Linear Technology/Analog Devices App Note, Mar 31st 2010

Low-Battery Indicator Uses Fleapower - 4-Sep-03 EDN-Design Ideas It is always desirable to use a low-battery indicator that consumes as little power as possible.  For a 9V, 450-mAhr alkaline battery, a 50-µA low-battery indicator can by itself run the battery down in a littlethan a year.  Battery-powered devices that need to run continuously for a long time require battery indicators that consume minimal power Design by Yongping Xia, Navcom Technology, Redondo Beach, CA

Low-battery voltage cutoff consumes just 1 mA - 09/11/98 EDN-Design Ideas NOTE : File has several circuits, please scroll to find this one.  A low-battery voltage-cutoff circuit prevents overdischarge of a rechargeable battery.  An obvious requirement of this circuit is extremely low power consumption.  Figure 1a's simple circuit has a measured current consumption of approximately 1.2 mA and uses only two Design by Yongping Xia, Teldata Inc, Los Angeles, CA

Low-Power Audio Amplifier using BC109C along with BD679 & BD680 Darlington pairs - As can be seen from the circuit diagram we are really using five transistors as the BD679 and BD680 are "Darlington" pairs of transistors.  The led must be a green led for correct operation.   (The voltage across a green led is higher than the voltage across a red led.) When using a 12v supply the voltage at T1 collector should be  (about) 5v and at T2 base  (about) 7v.  This amplifier will be unstable  (it will oscillate) without the 4k7 variable resistor connected to the input.   __ Designed by © David Hoult

Low-Power CMOS oscillator has push-pull output - 04/01/04 EDN-Design Ideas Digital oscillators often generate TTL- or CMOS -level outputs, referred to ground.  Generating a symmetric bipolar output with respect to ground presents a challenge.  In this design, four 1.5V flashlight cells create ±3V voltage sources, and the midpoint of cells acts as the ground reference (Figure 1) .  The oscillator at the input, based on the R1C1 time constant, generates Design by Shyam Sunder Tiwari, Sensors Technology Private Ltd, Gwalior, India

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