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

Last Updated: October 24, 2017 02:55 PM

Circuits Designed by Dave Johnson, P.E. :

Shadow Activated Motion DetectorThe hobby circuit below works quite well in typical indoor room lighting.  I would not recommend its use in direct sunlight.  Two small PIN photodiodes positioned about one inch apart form a shadow detector.  With no shadow cast on the devices, both device . . . Hobby Circuit designed by David A. Johnson P.E.-August, 2005

Simple Circuit Wire Security Loop AlarmA wire loop is used to protect valuable objects in this alarm circuit.  The circuit is powered by a 9v battery.. . . Circuit by David Johnson P.E.-December, 2004

Slotted-Type Optical Interrupter Draws MicroampsThis circuit is great for battery-powered systems that use slotted type optical interrupters.  It draws only 10uA from a 3v battery that should allow up to 5 years of operation from a lithium battery . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Solid State Relay Requires Only 50ua Drive CurrentThis circuit demands a control current that is 100 times smaller than that needed by a typical optically isolated solid state relays.  It is ideal for battery-powered systems.  Using a combination of a high current TRIAC and a very sensitive low current SCR. . . Circuit by David A. Johnson P.E.-June, 2000

SSR Requires Ultra Low Control CurrentMost solid state relays require at least 5ma and often more input control current, to fully turn on the device.  But such current levels often force battery powered circuits to use excessively large batteries.  The relay hobby circuit shown below demands only 50uA of input current . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Supercapacitor Voltage Limiting CircuitSupercapacitors are working their way into more and more applications where electrical energy needs to be stored.  These robust devices can be charged and discharged 1000s of times and will typically outlast a battery. . . Circuit by David A. Johnson P.E.-March, 2010

Switch Detects Audio SignalThis circuit will activate a transistor switch when it detects at least 50mv peak to peak of an audio signal.    It could be used to turn on a relay, routing the signal to were it is needed.. . . Circuit by David Johnson P.E.-July, 2006

Ten-Second Ultra Lower Power OscillatorThis circuit works much like the classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery.  It is highly stable under varying temperature and supply voltages. . . Circuit by David A. Johnson P.E.-May, 2000

Tester for Modulated LightThis battery powered circuit will work from DC to 500KHz.  It is designed to connect to an oscilloscope to monitor the light level changes and modulated signals . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

Thermocouple Temperature Activates RelayVoltage from a high temperature thermocouple activates a relay when the sensor detects a temperature above 1000 degrees F. . . Circuit by David Johnson P.E.-July, 2006

Three-Volt Low Battery Voltage FlasherMany battery powered devices use two AA alkaline cells.  Often you will not know when it is time to replace the batteries until the device powered by them actually stops operating.  The hobby circuit below can be connected to a 3v battery, to give you some . . . Hobby Circuit designed by Dave Johnson P.E.-January, 1998

Three-Volt Powered Very Loud BeeperGetting a high sound intensity from a piezoelectric type beeper is not easy when the available DC supply is only 3v.    The circuit below is not only efficient but produces a very intense sound.    The circuit combines a voltage boost section with a resonant . . . Hobby Circuit designed by David A. Johnson P.E.-February, 2009

Touch Activated SwitchThis circuit provides about one watt of non-isolated DC power for an automotive type 12v LED array lamp in addition to a standard incandescent table lamp.. . . Circuit by David Johnson P.E.-January, 2002

Touch Alarm for Door KnobI designed this hobby circuit many years ago and it seems be a very popular construction project.  Many companies offer simple alarm devices for personal use in bedrooms or hotel rooms.  A metal chain attached to a box holding the electronics is place . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2000

Transistor-Switch Detects Audio SignalFor some audio systems it is desirable to have an automatic switch circuit turn on other devices, such as an amplifier, if an audio signal is detected on one line.  The hobby circuit below will activate a transistor switch when it detects at least 50mv peak to peak of an audio signal.  The switch could be used to turn on a relay, routing the signal to where it is needed.  A single 3v lithium cell will power the electronic circuit for about 5 years . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

Two Transistor OscillatorsThis page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 micro amp of current. . . Circuit by Dave Johnson P.E.-December, 2002

Two-Transistor Low Power OscillatorsThis page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 micro amp of current . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2002

Ultra Low Current OscillatorHere is a challenge.  Design an astable oscillator which draws only a few nanoamps of current from a +3v supply.  I gave this some thought and came up with the circuit below.  I used some pretty standard parts except for three surface mounted 1000M resistors I had on hand.  The oscillator frequency measured a low 1Hz frequency and the average current was a very low 3 nanoamps.  If I had some higher resistors values handy, I think I could have gotten the current down below one nanoamp. . . Circuit by David Johnson P.E.-March, 2009

Ultra Low Power 32Khz Crystal OscillatorI have used this circuit many times when I needed a low frequency reference, which did not draw much power.  With the components show, the current from a 3v battery is less than 1.2 microamps . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2004

Ultra Low Power Latching Relay CircuitThe circuit below takes advantage of some inexpensive small super capacitors.  The circuit pumps 6 volt pulses into the separate 5 volt latching and unlatching relay coils.  A short 25ms pulse is all that is needed to flip the relay states.  A third super capacitor is used to supply a higher peak current than a small lithium cell might otherwise be able to supplyCircuit Solution by David A. Johnson P.E.-April, 2007

Ultra Low Power LED FlasherThe efficiency of some newer LEDs is amazing.  Some of the latest green LEDs can launch blinding light with just one milliamp of current.  I take advantage of one of these newer devices in the circuit below.  The flashing circuit uses a classic multivibrator . . . Hobby Circuit designed by David Johnson P.E.-December, 2008

Ultra Lower Power OscillatorThis circuit works much like the classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery.  It is highly stable under varying temperature and supply voltages. . . Circuit by Dave Johnson P.E.-May, 2000

Universal Flasher using a Latching RelayLatching relays are nifty devices.  Most contain two separate coils.  When a voltage is applied to one coil the relay latches in one state and stays in that state until voltage is applied to the unlatch coil.  Since the latching and unlatching pulses only . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2005


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

Shadow Activated Motion Detector -  The hobby circuit below works quite well in typical indoor room lighting.  I would not recommend its use in direct sunlight.  Two small PIN photodiodes positioned about one inch apart form a shadow detector.  With no shadow cast on the devices, both device . . . Hobby Circuit designed by David A. Johnson P.E.-August, 2005

Simple Circuit Wire Security Loop Alarm -  A wire loop is used to protect valuable objects in this alarm circuit.  The circuit is powered by a 9v battery.. . . Circuit by David Johnson P.E.-December, 2004

Simplify the Design of 1-Cell Li+ Battery-Operated Devices -  App Note 4181-- 3/20/2008 --  (add 5/08) __ Maxim Integrated

Single Supply, Micropower Sample & Hold -  Two op amp buffers, CMOS switches and a low leakage capacitor create a simple sample/hold circuit.  The LT1006 has the ability to speed up response and reduce supply current through pin 8.  When sampling the amplifiers are sped up to acquire signals in just 20us.  When put into hold mode the supply current is throttled back to only 250uA__ Linear Technology/Analog Devices App Note, Jun 21, 2011

Single Supply, Micropower, Second Order Lowpass Filter with 60Hz Notch -  The first section is a standard low-pass filter with Fc=40Hz.  The second section is a notch filter tuned to eliminate 60Hz mains pickup from the signal.  __ Linear Technology/Analog Devices App Note, Jun 21, 2011

Slotted-Type Optical Interrupter Draws Microamps -  This circuit is great for battery-powered systems that use slotted type optical interrupters.  It draws only 10uA from a 3v battery that should allow up to 5 years of operation from a lithium battery . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Solar Engine that is MicroPower -  Voltage-Controlled Solar Engine: Ken Huntington's fairly complex, but very efficient "micropower" solar engine design.  No 1381s or ICs needed.   __ Designed by Ken Huntington

Solar-Powered 2.2V Supply & 1.8V LDO with Li Battery Backup & Run Threshold Set to Battery Minimum Voltage -  The LTC3104 is a high efficiency, monolithic synchronous step-down converter using a current mode architecture capable of supplying 300mA of output current.  The LTC3104 includes an integrated, adjustable 10mA LDO to power noise sensitive functions.  Additionally, the LTC3104 includes an accurate RUN comparator, thermal overload__ Linear Technology/Analog Devices App Note, Dec 5th 2011

Solar-Powered 2.2V Supply with Li Battery Backup & Run Threshold Set to Battery Minimum Voltage -  The LTC3103 is a high efficiency, monolithic synchronous step-down converter using a current mode architecture capable of supplying 300mA of output current.  Additionally, the LTC3103 includes an accurate RUN comparator, thermal overload protection, a power good output and an integrated soft-start feature to guarantee that the__ Linear Technology/Analog Devices App Note, Dec 5th 2011

Solid State Relay Requires Only 50ua Drive Current -  This circuit demands a control current that is 100 times smaller than that needed by a typical optically isolated solid state relays.  It is ideal for battery-powered systems.  Using a combination of a high current TRIAC and a very sensitive low current SCR. . . Circuit by David A. Johnson P.E.-June, 2000

SOT-23 Micropower Rail-to-Rail Op Amps Operate with Inputs Above the Positive Supply -  DN221 Design Notes__ Linear Technology/Analog Devices

Speedy logic translator uses little power -  07/08/98 EDN-Design Ideas In handheld equipment, component count and power consumption are critical considerations.  This design idea uses only a few transistors to configure a high-speed output stage of an RS-232C link while draining few precious milliamperes from the batteries.  In general __ Circuit Design by Davis Magliocco, CDPI, Scientrier, France

SSR Requires Ultra Low Control Current -  Most solid state relays require at least 5ma and often more input control current, to fully turn on the device.  But such current levels often force battery powered circuits to use excessively large batteries.  The relay hobby circuit shown below demands only 50uA of input current . . . Hobby Circuit designed by David Johnson P.E.-June, 2000

Supercapacitor Voltage Limiting Circuit -  Supercapacitors are working their way into more and more applications where electrical energy needs to be stored.  These robust devices can be charged and discharged 1000s of times and will typically outlast a battery. . . Circuit by David A. Johnson P.E.-March, 2010

Switch Detects Audio Signal -  This circuit will activate a transistor switch when it detects at least 50mv peak to peak of an audio signal.    It could be used to turn on a relay, routing the signal to were it is needed.. . . Circuit by David Johnson P.E.-July, 2006

Ten-Second Ultra Lower Power Oscillator -  This circuit works much like the classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery.  It is highly stable under varying temperature and supply voltages. . . Circuit by David A. Johnson P.E.-May, 2000

Tester for Modulated Light -  This battery powered circuit will work from DC to 500KHz.  It is designed to connect to an oscilloscope to monitor the light level changes and modulated signals . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

The MicroPower Solar Engine -  A 'micro power solar engine' has been a goal since my introduction to BEAM Robotics.  I believe that if there wasn't one before, I there is one now.  What I'm presenting to you looks very similar to one of the circuits found in Steven Bolt's web pages.  As you will see, I made only minor changes to that design and not without help.   __ Designed by Ken Huntington

Thermocouple Temperature Activates Relay -  Voltage from a high temperature thermocouple activates a relay when the sensor detects a temperature above 1000 degrees F. . . Circuit by David Johnson P.E.-July, 2006

ThinSOT Micropower Buck Regulator has Low Output Ripple -  DN373 Design Notes__ Linear Technology/Analog Devices

Three-Volt Low Battery Voltage Flasher -  Many battery powered devices use two AA alkaline cells.  Often you will not know when it is time to replace the batteries until the device powered by them actually stops operating.  The hobby circuit below can be connected to a 3v battery, to give you some . . . Hobby Circuit designed by Dave Johnson P.E.-January, 1998

Three-Volt Powered Very Loud Beeper -  Getting a high sound intensity from a piezoelectric type beeper is not easy when the available DC supply is only 3v.    The circuit below is not only efficient but produces a very intense sound.    The circuit combines a voltage boost section with a resonant . . . Hobby Circuit designed by David A. Johnson P.E.-February, 2009

Touch Activated Switch -  This circuit provides about one watt of non-isolated DC power for an automotive type 12v LED array lamp in addition to a standard incandescent table lamp.. . . Circuit by David Johnson P.E.-January, 2002

Touch Alarm for Door Knob -  I designed this hobby circuit many years ago and it seems be a very popular construction project.  Many companies offer simple alarm devices for personal use in bedrooms or hotel rooms.  A metal chain attached to a box holding the electronics is place . . . Hobby Circuit designed by Dave Johnson P.E.-May, 2000

Transistor-Switch Detects Audio Signal -  For some audio systems it is desirable to have an automatic switch circuit turn on other devices, such as an amplifier, if an audio signal is detected on one line.  The hobby circuit below will activate a transistor switch when it detects at least 50mv peak to peak of an audio signal.  The switch could be used to turn on a relay, routing the signal to where it is needed.  A single 3v lithium cell will power the electronic circuit for about 5 years . . . Hobby Circuit designed by David Johnson P.E.-July, 2006

Two Transistor Oscillators -  This page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 micro amp of current. . . Circuit by Dave Johnson P.E.-December, 2002

Two-Transistor Low Power Oscillators -  This page has two unusual two-transistor oscillators.  I set the component values for a low frequency application.  Both circuits draw only about 1 micro amp of current . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2002

Ultra Low Current Oscillator -  Here is a challenge.  Design an astable oscillator which draws only a few nanoamps of current from a +3v supply.  I gave this some thought and came up with the circuit below.  I used some pretty standard parts except for three surface mounted 1000M resistors I had on hand.  The oscillator frequency measured a low 1Hz frequency and the average current was a very low 3 nanoamps.  If I had some higher resistors values handy, I think I could have gotten the current down below one nanoamp. . . Circuit by David Johnson P.E.-March, 2009

Ultra Low Power 32Khz Crystal Oscillator -  I have used this circuit many times when I needed a low frequency reference, which did not draw much power.  With the components show, the current from a 3v battery is less than 1.2 microamps . . . Hobby Circuit designed by Dave Johnson P.E.-December, 2004

Ultra Low Power Latching Relay Circuit -  The circuit below takes advantage of some inexpensive small super capacitors.  The circuit pumps 6 volt pulses into the separate 5 volt latching and unlatching relay coils.  A short 25ms pulse is all that is needed to flip the relay states.  A third super capacitor is used to supply a higher peak current than a small lithium cell might otherwise be able to supplyCircuit Solution by David A. Johnson P.E.-April, 2007

Ultra Low Power LED Flasher -  The efficiency of some newer LEDs is amazing.  Some of the latest green LEDs can launch blinding light with just one milliamp of current.  I take advantage of one of these newer devices in the circuit below.  The flashing circuit uses a classic multivibrator . . . Hobby Circuit designed by David Johnson P.E.-December, 2008

Ultra Low Voltage Micropower Crystal Oscillator -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Ultra Low Voltage Nanopower Inverter  -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Ultra Low Voltage Nanopower LC Colpitts Oscillator -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Ultra Low Voltage Nanopower Two-Input NOR & NAND Gates -  Circuit Ideas for Designers App Note__ Advanced Linear Devices, Inc

Ultra Lower Power Oscillator -  This circuit works much like the classic 555 timer, but draws only about 1.5 microamps from a 3 volt battery.  It is highly stable under varying temperature and supply voltages. . . Circuit by Dave Johnson P.E.-May, 2000

UltraLow Power, 18-Bit, Differential PulSAR ADC Driver  -  A PC with Windows® XP or Windows 7 equipped with an USB port was used to run the PulSAR evaluation software.  , Getting Started The software was installed as described at www.  analog.  com/EVAL-CED1Z , and www.  analog.  com/AD7982_adc_EVAL-CED1Z The PulSAR evaluation software, which is LabVIEW® based, was used to control the Audio Precision input signals and also to monitor the ADC inputs and output.  The software allows the collection and processing of INL, DNL, and FFT data as shown in Figure 2, Figure 3, and Figure 4.  __ Analog Devices from the Lab

Universal Flasher using a Latching Relay -  Latching relays are nifty devices.  Most contain two separate coils.  When a voltage is applied to one coil the relay latches in one state and stays in that state until voltage is applied to the unlatch coil.  Since the latching and unlatching pulses only . . . Hobby Circuit designed by Dave Johnson P.E.-October, 2005

USB-GSM application with 5V USB input (500mA max) charging a 4.4mF super cap (3.4V at 800mA) & providing 1.8V at 400mA  -  The LTC3619 is a Dual 400mA/800mA monolithic synchronous buck regulator with an input supply voltage range is 2.5V to 5.5V, making it ideal for Li-Ion and USB powered applications __ Linear Technology/Analog Devices App Note, Mar 23, 2010

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

 


Imagineering Ezine    Discover Solar Energy Dave Johnson & Associates Faraday Touch Switches



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