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Last Updated on: Thursday, April 07, 2016 02:04 PM

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Low Power (Micro Power)
Dave's MicroPower Circuits:
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1 Line Telephone Line Status Indicator  -  This circuit monitors one phone line . . . [Circuit by David A. Johnson P.E.,  06/10/00]

1.5v LED Flasher Version A  -  Many published circuits that flash LEDs need 3 volts or more.  This circuit uses only a single inexpensive C-MOS IC and flashes the LED for a full year on a single 1.5 volt AA alkaline battery cell. The circuit uses a charge pump technique to provide . . . [Circuit by David Johnson P.E.,  06/04/00]

1.5V Touch Activated Switch  -  A single 1.5v silver oxide button cell powers this complete touch activated switch circuit for 5 years.  It features both a normally open and a normally closed set of solid-state switch thermals.  It also has an adjustable sensitivity, which can be set for a touch capacitance change as small as 1 picofarad. . . . [Circuit by David Johnson P.E.,  01/18/02]

10 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 Dave Johnson P.E.,  05/29/00]

12v Touch Switch Exciter Circuit  -  This circuit is designed to generate a 20KHz pseudo sine wave signal that can power about 50 remote touch activated switch circuits.  It can support a cable length of about 2500 feet.  A typical remote switch circuit is also shown as well as a receiver circuit for those switches. . . . [Circuit by Dave Johnson P.E.,  02/10/02]

2 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 David A. Johnson P.E.,  12/14/02]

3 Volt 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 Dave Johnson P.E.,  01/01/98]

32Khz Ultra Low Power 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 . . . [Circuit by David A. Johnson P.E.,  12/18/04]

3v 2hz Oscillator  -  This is yet another method to generate low frequency output pulses. The circuit uses an inexpensive under-voltage monitor IC and a couple of cheap MOSFETs. It could easily be modified to produce pulse frequencies from about one cycle per minute to a maxim . . . [Circuit by David Johnson P.E.,  06/17/00]

3v Powered 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  . . . [Circuit by David Johnson P.E.,  02/18/09]

40Khz Burst Laser Diode Driver  -  Some laser tag or simulated combat games can use this circuit to send short bursts of modulated laser light at the opponent's vest, equipped with a matching light receiver. The circuit operates from three 1.5v cells (4.5v) that should provide enough energy . . . [Hobby Circuit designed by David Johnson P.E.,  06/04/00]

40Khz Light Detector With High Ambient Light Immunity  -  This circuit is designed for detecting infrared light modulated at around 40KHz.  Itís feedback scheme cancels much of the DC component from ambient light.  Itís conversion factor is about 100 millivolts per microwatt of 900nm light.  . . . [Circuit by Dave Johnson P.E.,  07/11/06]

40KHz Light Detector with Sunlight Immunity  -  This hobby circuit below was designed to turn on an external 12v relay, whenever it detects light from a nearby LED light source, modulated at 40KHz to 50KHz.  This circuit was originally designed to operate from a fast moving vehicle . . . [Hobby Circuit designed by David Johnson P.E.,  07/11/06]

50ua Current Drives Solid State Relay Requires Only  -  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 Dave Johnson P.E.,  06/03/00]

9v 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 Dave Johnson P.E.,  12/06/09]

9v Battery Voltage Monitor  -  This circuit turns on a LED whenever the voltage of a standard 9v battery connected to the circuit drops below 7.2 volts.  It uses a LTC1440 comparator, which also contains a 1.18v reference diode.  In standby mode, the circuit draws only 4uA . . . [Circuit by David A. Johnson P.E.,  07/09/06]

9V Pulse Generator  -  It is hard to design a pulse generator that produces clean logic pulses while drawing very low current. This circuit is designed to produce short 2mS pulses at a rate of one per second while drawing only 1 microamp from a 9 volt battery . . . [Circuit by Dave Johnson P.E.,  06/03/00]

Advertising Badge with Flashing LED #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 Dave Johnson P.E.,  03/26/02]

Advertising Badge with Flashing LED #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 Johnson P.E.,  03/26/02]

Alarm Sounds At Freezing Temperatures  -  This electronic hobby circuit below is designed to activate a beeper alarm, whenever the outside air temperature is below 0 degrees C (32F) .  A 9v battery powers the hobby circuit.  The average 9ua current is so low that the battery should last for many years . . . [Hobby Circuit designed by David A. Johnson P.E.,  07/11/06]

Alarm-Piezo Device detects Motion  -  Using a piezo device, this circuit will activate a beeper whenever the circuit is moved.  It could be used as an earthquake alarm . . . [Circuit by Dave Johnson P.E.,  07/09/06]

Audio Activated Switch  -  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 A. Johnson P.E.,  07/09/06]

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