Electronics Design - Otakar Priboj

White LED torch with 1W LUXEON . good for bush waking.

Circuit employ SMD components. Size of the board diameter 14.5 mm. This can drive Luxeon up to 400 mA from 2 NiMH batteries. I used Zetex drivers ZXSC300E5CT or ZXSC310CT

with possibilities to use shut down pin for dimming control. With 2 AA 1600 mA NiMH batteries run time for torch is 2 hours. Test with 2 D 4000 mA confirm rum time of 8 hours.

Text link to Schematic
Image of Zetex driver PCB
Image of PCB-Pil driver board.
Image of assembled torch.
Image of 3 W Luxeon driver board.
Image of 3 W Luxeon torch.

NEW!!! DC/DC Converters for Powering Luxeon LED's

	Sexiest LED and driver in the galaxy!!! (Milky way) This was checkout for facts and approved by ET. Please if you don't agree don't look. New prototype of driver for 1WLuxeon and 3 W Luxeon. Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Each driver is tuned for best performance.
	Mimi<300 driver 300mA from 1.5V
	Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Operates from 1 Alkaline / NiMH AA / AAA cells. Typical output 300mA from AA cells. (tested with 1W Luxeon and 1.5V Vin ) Converter can by made as 9.0mm diameter size if desired. Operating voltage range from 0.5V - 1.7V Hand assembled circuit is tuned and tested ???? Each one will get a 10 minute burn in test so everything gets up to temperature. Link to Schematic mimi300_t.pdf Link to PCB driver board mimi300_t_pcb.pdf Image of 1 W Luxeon Mimi<300 driver board.
	Mimi<800 driver 800mA from 3.0V
Future development Please visit in future.	Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Operates from 2 Alkaline / NiMH D / AA / AAA cells. (minimum 2300mA NiMh AA or D size sells recommended). Typical output 800mA from AA Alkaline cells (tested with 3W Luxeon and 3.0V Vin). Converter can by made as 9.0mm diameter size if desired. Operating voltage range from 1.5V - 3.4V. Hand assembled circuit is tuned and tested. ???? Each one will get a 10 minute burn in test so everything gets up to temperature. Input voltage maximum 3.2V !!!, can be design and tuned to accept V_in maximum 4.2V. Link to Schematic mimi800_t.pdf Link to PCB driver board mimi800_t_pcb.pdf Image of 3 W Luxeon Mimi<800 driver board.
	Mimi>1000 driver 1000mA from 6.0V
Future development Please visit in future.	Measures 13.9 mm (??? inch) diameter x 6.7 mm (??? inch) height. Operates from 4 Alkaline / NiMH D / AA cells. (2300mA NiMh AA or D size sells recommended) Typical output 1000mA from D / AA cells. (tested with 3W Luxeon and 4.80V Vin ) Operating voltage range from 4.0V - 6.0V Hand assembled circuit is tuned and tested ???? Each one will get a 10 minute burn in test so everything gets up to temperature. Link to Schematic mimi1000_t.pdf Link to PCB driver board mimi1000_t_pcb.pdf Image of 3 W Luxeon Mimi>1000 driver board.
	Maxi> 70012 driver SMD
Future development Please visit in future.	Will drive 3x 3W luxeon in series. Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Operates from 12V. Typical output 700mA from 12V Battery or power supply. (tested with 3x 3W Luxeon and 12.0V Vin) Converter can by made as 9.0mm diameter size if desired. Operating voltage range from 11V - 14.4V Used for in home lighting - solar powered house. Car, Caravan or Truck.
	Maxi> 70012 driver SMD
Future development Please visit in future.	Will drive 3x 3W luxeon in series. Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Operates from 24V. Typical output 700mA from 24V Battery or power supply. (tested with 3x 3W Luxeon and 24.0V Vin) Converter can by made as 9.0mm diameter size if desired. Operating voltage range from 20V - 28.8V Used for in home lighting - solar powered house. Car, Caravan or Truck.

NEW!!!
DC/DC Converters for Powering Luxeon and Golden Dragon LED's
from 12V,
24V,
48V.

Ideal for Solar
powered house.

Sepic 12V / 48V driver

First test of prototype PC board sepic_cal_eff.jpg click to enlarge	One driver design for ALL!!! Excellent Led driver from wide imput voltage power supply I initial tested this design with voltage range 9V to 30V with power supply regulator 7812. With different power supply regulator will run from 12V to 60V. Drive 3 to 9 Led's from 12V power supply @ 730mA. 3 to 14 Led's from 24 to 60V power supply @ 730mA. Note: Tested with 9 Luxeon III @ Input voltage 12V to 60V . With 12V power supply driving electronics have only 9V which is too low for driving MOSFET's. fixed this problem with bootstrap link. SEPIC Single-Ended Primary Inductance Converter (step-up or step-down voltage converter) Sepic converter driver was chosen because it have ability to have low or high input voltage and same time have Zero-Ripple on input and can drive 3* to 14 - 3 W led's. This driver can be used in 12V-24V- 48V house lighting system and in emergencies can be used in car 12V battery. 24 V solar system and in same time in car. * less than 3 Luxeon its overkill to use this driver I will design new simple driver with SMD. Universal Luxeon driver will drive 3 - 14 3W Luxeon III, (Luxeon K2) or Golden Dragon in series. Features Will drive 3 -14 3 W Led's. Operating voltage range from 10V / 60V. (10V if used bootstrap link). Typical output 700mA - 750mA. Open-circuit output protection. Operate from 10V to 60V Battery DC power supply or AC. Output fine current adjustable posible by user. Pulse width modulation dimming. Dimming possible by adding trimpot. Efficiency 85% to 93% see graf sepic_cal_eff.jpg Measures 146 mm (??? inch) x 67 mm (??? inch) height. Ideal Luxeon driver for Solar powered house, Car, Caravan or Truck. Step-up/step-down (SEPIC) design. Note: For AC ad rectifier bridge and output filter capacitor 2200uF / 63V. Maximum input voltage 60V, Maximum output voltage 60V. Note: Tested with 9 Luxeon III and can be used from 3 to 14 Led's. Driver for 3 - 9 Led's from 12V and 3 - 14 Led's from 24V-60V 3W Luxeon III. I am using this driver in my 24 V solar house set-up. Link to Schematic sepic12_48.pdf Link to PCB driver board sepic12_48pcb.pdf Features l fixed current outputs at 330, 650, 980 & 1350mA l variable output current version also available l wide range of input voltages (3.6 - 20-volts) l higher drive for new red/amber 3W Luxeon l step-up/step-down (SEPIC) design l open-circuit output protection l board only 30mm x 35mm
	Maxi> 70012 driver SMD
Sepic 12V / 30V driver 1- 6 Luxeon III First test of prototype PC board	Will drive 3x 3W luxeon in series. Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Operates from 12V. Typical output 700mA - 1000mA from 12V Battery or power supply. (tested with 3x 3W Luxeon and 12.0V Vin) Converter can by made as 9.0mm diameter size if desired. Operating voltage range from 11V - 14.4V Used for in home lighting - solar powered house. Car, Caravan or Truck
	Maxi> 70024 driver SMD
Future development Please visit in future.	Will drive 3x 3W luxeon in series. Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Operates from 24V. Typical output 700mA - 1000mA from 24V Battery or power supply. (tested with 3x 3W Luxeon and 24.0V Vin) AA Alkaline cells (tested with 3W Luxeon and 3.0V Vin) Converter can by made as 9.0mm diameter size if desired. Operating voltage range from 20V - 28.8V Used for in home lighting - solar powered house. Car, Caravan or Truck.

Solar battery charger controller Sem1 and Sem2 with power module can switch 120 A to 12 or 24 V battery.
One switching module can switch 60 A, and use 6 Mosfets 60 A each on resistance 0.02R.
Voltage drop its minimal. Battery voltage can be changed from 12 to 24 V just with removing link.

Solar Battery charging controller SEM 1 - PSM30 & PSM60
Future development Please visit in future. Image of SolarElectronics Module SEM1	SEM1 is Solar Electronics Module, which control power module PSM30 or PSM60 and switch the power source on and off as required. This is a very efficient method and can be used with alternative charging methods. You can configure solar regulator which 1x PSM30 for switching of 30A and you can connect 1 x PSM30 to 5 x PSM30. In other words you can expand of current handling of solar regulator in future and save money. 1x PSM60 for switching of 60A and you can connect 1 x PSM60 to 5 x PSM60. In other words you can expand of current handling of solar regulator in future and save money. Field selectable 12 or 24 Voltage. It can be supplied different voltages 36V, 48V. Fluent battery charged voltage level from 13.4 to 17.0 volts. ( 26.8 to 34.0 volts for 24V ) Battery Temperature Compensation.(Optional) This Solar Electronics Module, lets you charge a lead-acid battery from a solar panel, at current up to 150A /100A. ( 5x 30A / 5 x 20A depend on version of system ) You can configure solar regulator which 1x PSM30 for switching of 30A ( voltage drop is only 0.15V ) or 20A ( voltage drop is only 0.1V ) and in future you can expand your system to 60A / 40A , 90A / 60A,. 120A / 80A or 150A / 100A. ( add on PSM30 for additional 30A / 20A capacity ) You can configure solar regulator which 1x PSM60 for switching of 60A ( voltage drop is only 0.15V ) or 20A ( voltage drop is only 0.1V ) and in future you can expand your system to 120A / 180A , 90A / 60A,. 120A / 80A or 150A / 100A. ( add on PSM60 for additional 60A capacity ) 2 LED's status indicators Yellow - CHARGING and Green - FULL / FLOAT 1 LED status indicator for load disconnect ( 10.8V on 12V / 21.6V on 24V ) Red - ON . By using MOS circuitry and low current LED's, the quiescent current, and power consumption of the regulator is very low. It will work with 12V, 24V, 36V, 48V. lead-acid, deep cycle, gel cells, lead-acid car, truck or boat batteries. Right : Solar Electronics Module SEM1 assembled form.
Solar Battery charging controller SEM2 - PSM30 & PSM60
Image of SolarElectronics Module SEM2	SEM2 is Solar Electronics Module, which control power module PSM30 and switch the power source on and off as required. This is a very efficient method and can be used with alternative charging methods. You can configure solar regulator which 1x PSM30 for switching of 30A and you can connect 1 x PSM30 to 5 x PSM30. In adder words you can expand of current handling of solar regulator in future and save money. Field selectable 12 or 24 Voltage. It can be supplied different voltages 36V, 48V. Fluent battery charged voltage level from 13.4 to 17.0 volts. ( 26.8 to 34.0 volts for 24V ) Battery Temperature Compensation. This Solar Electronics Module, lets you charge a lead-acid battery from a solar panel, at current up to 150A /100A. ( 5x 30A / 5 x 20A depend on version of system ) You can configure solar regulator which 1x PSM30 for switching of 30A ( voltage drop is only 0.15V ) or 20A ( voltage drop is only 0.1V ) and in future you can expand your system to 60A / 40A , 90A / 60A,. 120A / 80A or 150A / 100A. ( add on PSM30 for additional 30A / 20A capacity ) 2 LED's status indicators Yellow - CHARGING and Green - FULL / FLOAT 3 LED's status indicators for load disconnect which control power module PLM25 and switch the power source off as battery reach levels 3 ; 2 ; 1 . Red - LED3 ON .( 10.8V on 12V / 21.6V on 24V ) Red - LED2 ON . ( 11.0V on 12V / 22.0V on 24V Red - LED1 ON . ( 11.2V on 12V / 22.4V on 24V ) 1 LED status indicator for diversion of current from solar array ( via power diversion module or additional PSM30 ) to another battery or water pump, energy is not wasted. To prevent fast switching on and off introduced is time 2 minutes. LED status indicator for load disconnect ( 10.8V on 12V / 21.6V on 24V ) Red - ON . By using MOS circuitry and low current LED's, the quiescent current, and power consumption of the regulator is very low. It will work with 12V, 24V, 36V, 48V lead-acid, deep cycle, gel cells, lead-acid car, truck or boat batteries. Right : Solar Electronics Module SEM2 assembled form.

"Cool Power" a&o 505 Laboratory Power Supply

"Cool Power" from O.P. SOLAR , a&o 505 Single Output 0 - 50V, 0 - 5A.

A new range of rugged, high specification power supply that have been designed for both the industrial and education markets. A versatile variable laboratory / bench power supply, capable of operation in both constant current and constant voltage mode with automatic cross over ; constant current or constant voltage is indicated by 2 LED's. Dual 3 digit Led display allow current and voltage to be accurately pre-set with the output switch in position "off" for voltage pre-set , and in position "set I (load on)" for current pre-set and the output to be precisely monitored with the output switch set to "load on". Voltage and current can be set by means of fine 10 turn potentiometer controls. Voltage to a precision of 100 mV , and current to a precision of 10 mA. Current limit may pre-set prior to a load being connected. LED's show whether the supply is operating in constant voltage or constant current mode. Power supply can operate in to short circuit indefinitely. By applying SCR pre-regulator voltage drop on regulating transistors remain approximately 7V.

Futures:

High quality, high power linear regulation.
Low noise and excellent transient performance.
Tree digit display of voltage and current.
0.1% accuracy, 0.1V Volt and 0.01A Amps resolution.
Simultaneous metering of voltage and current.
Voltage and current setting can be viewed prior to being applied.
True constant voltage or constant current.
Constant voltage and constant current indication (LED).
(Constant voltage or constant current mode with automatic crossover).
Power supply can operate in to short circuit indefinitely.

"Cool Power" a&o 505 LABORATORY POWER SUPPLY
"Cool Power" from O.P. SOLAR , a&o 505 Single Output 0 - 50V, 0 - 5A

Specification :

Mains input 220/240V ac +/- 10 % 50/60 Hz
Output 0 to 50V / 5A
Load regulation ( output change for zero to full load change ) < 0.1mV eff
Constant voltage approx. < 1mV eff
Constant current approx. < 0.01%
Internal resistance
Constant voltage approx. 10 mOhm
Constant current approx. 20KOhm
Ripple and noise < 5mV pk-pk

Power supply can operate in to short circuit indefinitely.
Maximum internal dissipation in all conditions. (On regulating transistors) < 40W

Link to Schematic - op_1.pdf and op_2.pdf
Link to PCB driver board - op004_1pcb.pdf

Solar switching regulator

Image of Solar Regulator OP004
Solar Regulator OP004 assembled form. OP004/12V/20A

Published in Silicon Chip January 1994 "Switching regulator for solar panels."

In the simplest solar panel plus battery setup, all you need is a diode to isolate the panel from the battery . This prevents the battery from discharging via the solar panel when it is not illuminated by the Sun.This is OK for a temporary setup but unless the solar panel is only trickle charging the battery , you will eventually run up against the problem of over-charging. Over-charging a lead-acid battery causes gassing, which can significantly reduce its life.To avoid over-charging the battery you need a regulator circuit so that the solar panel can charge the battery at its maximum current output until, reaches full charge. At that point, the regulator disconnects the panels from the battery and no further charging take place. The regulator can be build in two versions (10-amp or 20-amp) & can be used to charge a 12V or 24V battery bank.

OP004/12V/10A & OP004/12V/20A
OP004/24V/10A & OP004/24V/20A

Solar Regulator OP004 is a switching regulator, switches the power source on and off as required. This is a very efficient method and can be used with alternative charging methods.

This Regulator lets you charge a lead-acid battery from a solar panel, at current up to 20A ( depending on version of Regulator ). By using MOS circuitry and low current LED's, the quiescent current, and power consumption of the regulator is very low. It will work with 12V, 24V lead-acid deep cycle, gel-cells, lead-acid car, truck or boat batteries. ( It can be set also for 36V )

Solar switching regulator is available in short form kit version. PCB OP008, on-board components , for price look PRICE LIST. We can also provide build up service for our kits.

Link to Schematic - op004_1.pdf and op004_2.pdf
Link to PCB driver board - op004_1pcb.pdf
Full photostat copy of the article can be obtained from www.siliconchip.com.au

Inverter for fluorescent lights

Original inverter for fluorescent lights

fluoro inverters2

Inverter for fluorescent lights with different transformer

Published in Silicon Chip February 1991 "Three inverters for fluorescent light"

Fluorescent tube are one of the most efficient forms of electric lighting but because of their high voltage requirements their are rarely used unless 240V AC mains power is available. The particular attraction of fluorescent lights in these applications is that they are so highly energy efficient - much better than incandescent lamps. Yet are many applications where the high efficiency of fluorescent tubes could be highly useful. These range from portable emergency lighting to lighting for recreational vehicles, caravans, boats, and on homes and farms. In fact, if a pinpoint light source or a concentrated beam is not required, then fluorescent lighting should be the first choice, because of its efficiency. This inverter provide the necessary high AC voltage to drive a fluorescent tube from a 12V DC (24V/48V) supply and at a high efficiency.

Sine wave - NO interference's.
One fluorescent inverter for the range of fluorescent tubes from 5W to 2D 21W.
Change tube has no effect on the fluorescent inverter.
High frequency switching for low power consumption.
Standard 12V / 24V DC ( optional 48V ) supply.
Power consumption on 12V - 7W /0.48A ; 9W /0.63A ; 11W /0.78A ; 2D 16W /0.88A ; 2D 21W /0.95A

This view shows the versatile fluorescent inverter 7W -16W.

Link to Schematic - fluoro_1.pdf
Link to PCB driver board - fluoro_1pcb.pdf
Full photostat copy of the article can be obtained from www.siliconchip.com.au

Electronics projects published in Australian magazines.
Projects : Published in Silicon Chip, Electronic Australia and Soft Technology - now ReNEW.
The Silicon Chip January 1991 Build a bigger laser.	Helium tube 5mW laser for laser light show.
The Silicon Chip February 1991 Three inverters for fluorescent light.	Three inverters 1 universal from 7W tube to 2D 16W tube, 18W tube and 36W tube.
Electronics Australia August 1992 Visible laser diode pointer.	3 mW Visible laser diode pointer.
Soft Technology number 46 ( now ReNEW ) Build yours own 12V fluoro inverter.	Universal 12 and 24V fluoro inverter.
The Silicon Chip January 1994 Switching regulator for solar panels.	Switching regulator for solar panels. 12 / 24V version and 10A/20A (OP004)
Full photostat copy of all articles (excluding ReNEW ) can be obtained from www.siliconchip.com.au

White LED torch with 3W LUXEON . Proposed project for future development.

White led's Luxeon III, (Luxeon K2) or Golden Dragon.

One option I'm considering is using Luxeon III and use 2 Zetex drivers either ZXSC300E5CT or ZXSC310CT. Only difference ZXSC310CTD shut pin can be used for dimming control. In this configuration I can use 1 driver for 1/2 power and 2 driver for full power. I tested ZXSC300E5CT and ZXSC310CT in this configuration and circuit can drive Luxeon 3W from 3V delivering approximately 800mA.
Second option I'm considering is using Luxeon III and use step-down converter or microcontroller. Microchip have driver on they site. Buck Configuration High Power LED Driver AN874. The circuit is based on a buck topology switching power supply using the on-chip comparator peripheral within the PIC12F675 microcontroller. This microcontroller system can use only one switch and have 15 steps dimming control.
Microcontroller based Sepic (Single-Ended Primary Inductance Converter) converter for driving Luxeon and Golden Dragon LED Led's from 10 to 32V, 1 or 2 strings of six led's. Dimmer control, light intensity sensor for constant light output, can be used with natural lighting and IR sensor with timer no movement switch off..
Linear technology manufacture of special IC's for driving Led's. Examples are: LT 1618, LTC 3215 - 700mA Low Noise High Current LED Charge Pump, LTC 3490 - Single Cell 350mA LED Driver.
Sepic (Single-Ended Primary Inductance Converter) dc/dc converter for driving Luxeon and Golden Dragon LED Led's from 10 to 32V and if demand for 48V. Sepic was chosen for ability to work from wide range of input voltages and Zero-Ripple on input.

Solar power - Charger controllers.

PWM solar battery charger controller for 12V and 24V battery bank and if demand for 48V.
PWM solar battery PTM charger controller.

Proposed LED's driver project for future development. As you find out some of the project are already on this page.

< 5mm LED's Drivers for Lighting. Used for white , red, yellow. > Simple but reasonable efficient driver for 5mm Led's.

Single transistor driver for 1 and 3 LED's.
Two transistors driver for 1 LED.
Two transistors driver for 6 LED's.
Four transistors driver with current limit for 6 LED's.

< Luxeon 1W and 3W Drivers for Torch. > More powerful drivers for Luxeon III, (Luxeon K2) or Golden Dragon.

Zetex driver for 1W Led's. Step-up from 2-3V. I_out 350mA and 400mA to 500mA.
Zetex driver for 3W Led's. Step-up from 2-3.8V. /Bootstrap/ I_out 500mA to 700mA.
Sepic Zetex driver for 1W Led's. From 1.5-7V. /Bootstrap/ I_out > 300mA.
Sepic Zetex driver for 3W Led's. From 1.5-7V. /Bootstrap/ I_out > 300mA.

< Luxeon 3W Drivers for Solar Home Lighting. > Universal driver will drive 3 - 6 3W Luxeon III, (Luxeon K2) or Golden Dragon in series one or two strings.

Luxeon drivers from 12V; 24V; 48V. For 1W, 3W. / 1 - 6 Led's one string and two strings for 2x 6 Led's.

Drivers based on TL494 or SG3524.
Drivers based on Microchip microcontroller.
Drivers based on ONsemi.com PWM IC's MC34063A & MCV33163.

12 - 24V Sepic design (universal V_in) V_in 10V - 30V. Driver for 1 - 6 and from 24V 6 - 12 3W Luxeon III, (Luxeon K2) or Golden Dragon in series.

Drivers based on TL494.

24 - 48V Sepic / Push-pull design (universal V_in) V_in 20 - 60V. Universal Luxeon driver will drive 1 - 6 3W Luxeon III, (Luxeon K2) or Golden Dragon in series.

Drivers based on TL494 and SG3524.

12 - 24V Push-pull design (universal V_in) (see Note #)
24 - 48V Sepic / Push-pull design (universal V_in) (see Note #)
Dimmer control for driver or dimmer control included in driver.
Zetex based 12/ 24V driver / and dimmer control.

# After experience with sepic driver I will reconsider development of this design.

12V 3x 3W Luxeon
12V 3 - 6x 3W Luxeon

< Luxeon 3W Drivers for Solar Home Lighting. > Universal driver will drive 3 - 6 3W Luxeon III, (Luxeon K2) or Golden Dragon in series one or two strings.

ZXLD1350 350mA LED driver with internal switch (SMD design),

Contact : Otakar Priboj priboj-eled.com.au

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	White LED torch driver for 1 & 3 x 5 mm Led's.
	Two Single transistor drivers for 1 Led Left inductor for single transistor LED driver operate from 1.2 - 1.5V Operates from 1 Alkaline / NiMH AA / AAA cells. Can supply 25mA to 1 or 3 LED's. >?????Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Operating voltage range from 0.5V - 1.5V Simple circuit use only 5 components. Components from single camera can be used transformer - trigger transformer (after rewind), switching transistor. Components can be reclaimed from Computer Motherboards, Video cards, Hard disk drives - tantalum smd capacitors, diodes and ferrite RF rods. Transistor Q1 can be substituted with transistors reclaimed from Computer hard disk drives this all apply for capacitors. Note: Can be used components from single camera, transformer after rewind, switching transistor. Files in Acrobat pdf format Link to Schematic single_t.pdf Link to PCB driver board single_pcb.pdf
	Single transistor driver 1 or 3 Led driver Left inductor for single transistor LED driver from 1.2 1.5V Operates from 1 Alkaline / NiMH AA / AAA cells. Can supply 25mA or more to string of 3 LED's. Current is adjusted with R before potting in epoxy. ?????Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Operating voltage range from 0.5V - 1.5V Looks like mess, tangled cooper wires. Note: Can be used components from single camera, transformer after rewind, switching transistor. Simple circuit use only 5 components. Link to Schematic single_t.pdf Link to PCB driver board single_t_pcb.pdf
	White LED torch 10 and 12 x 5 mm Led's.
	Two transistor driver Left inductor for two transistor LED driver from 1.2 1.5V Operates from 2 Alkaline / NiMH AA / AAA cells. Can supply 25mA or more to string of 3 LED's. Current is adjusted with R before potting in epoxy. ?????Measures 10.6 mm (??? inch) diameter x 6.7 mm (??? inch) height. Typical output 300mA from AA cells. (tested with 1W Luxeon and 1.5V Vin ) Converter can by made as 9.0mm diameter size if desired. Operating voltage range from 2V - 3V Hand assembled circuit is tuned and tested Looks like mess, tangled cooper wires. Link to Schematic two_t.pdf Link to PCB driver board two_t_pcb.pdf