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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 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
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 |
