High power LED flashlight circuit, 6 LED for 1.5V AA battery

Last updated on April 16th, 2022 at 10:13 pm

This high power LED flashlight circuit look like a torch by use on 1.5V battery only so it can be used. Since small so Easy to carry in various places. And also very bright as well.

The technical information

Power supply : one 1.5V AA battery.
Maximum current used 200mA
Uses 6 white LED.
Small size PCB.

How it works

As usual, the LED light when a voltage is 1.8V or 2V,
We need a way to increase the voltage to rise, by the switching supply mode in step-up DC to DC converter circuit.

High power LED flashlight circuit, 6 LED for 1.5V AA battery

Figure 1 Circuit diagram of High power 6 LED Flashlight for 1.5V AA battery.

As Figure 1 is Circuit diagram of this project. By operation of the circuit is determined by Coil and C2. Which will serve as the production cycle frequency. The LC Frequency circuit with capacitors and capacitor alternately, cause frequency.

When we apply power supply voltage to circuit, the transistor TR1 will working. Then TR2 will work as well. In the meantime, C2 will charge store current. So all LEDs will go out. But when fully charging, TR1 will stop working result C2 discharge to all LEDs glow.

Learn: How to use 555 timer circuits

Since the charging and discharging very fast, cause we see them same still brightness. The capacitor-C1 will be filter the current to smooth.

How to builds.

Real PCB of high power 6 led flashlight for aa battery

This project is small and a few part so we can use a perforated board. Or use real PCB as Figure 2. Then assemple all parts on PCB and wiring as Figure 3.

Figure 2 the real PCB of this project.

Components layout and circuit assembling

Figure 3 the components layout.

Coil is about 100uH

The L1-inductor is 100uH as Figure 4 I measure it show you. And you can use any type that look like it.

Figure 4 Coil is about 100uH.

High power 6 LED Flashlight for 1.5V AA battery

Figure 5 The High power 6 LED Flashlight projects for 1.5V AA battery.

When completed circuit assembly Supply voltage range of 1.5V to the circuit.
Then slide the switch to position ON. The All LEDs will lit, the circuit is ready for use.
As Video below.

I want to see wavefrom across LEDs (all in parallel) through an oscilloscope panel.
We will see that high amplitupe about 3Vp-p it cause LEDs glow.

Note: AA battery we should is kind of alkali house. Because high performance

The parts list.
Resistors 0.25watts
R1: 10K
R2: 6.8K
R3: 100 ohms

Electrolytic capacitors
C1: 220uF 16V

Ceramic Capacitors
C2: 680pF 50V

Inductors coil
L1: 100uH Please how to build it here
TR1: CS9012__ 0.8A 40V PNP Transistors.
TR2-TR4: CS9013__0.8A 40V NPN Transistors.

PCB, 1.5V AABattery, etc.


I always try to make Electronics Learning Easy.


  1. Salim Khan

    Is there any formula to make 100uH inductor?

  2. Salim Khan

    Thanks for reply sir. The link you give me that I can Modify the toroidal coil.
    But In order to make any inductor accurately then formula is needed. If you have please share.

  3. hello sir,
    how many coli of wire need to make 100uh inductor..i mean how many times i rotate the wire to the coli because i don’t the meter to mesure it..

  4. Hi, Sk sahabaj

    Okay, Can you have compact fluorescent light bulb?
    In any project I use them.
    If be toroidal coil I turn wire about 10 times for 100uH at wire 24AWG no.

  5. @sk sahabaj.
    I am sorry to you. Please check all parts and wiring circuits again.
    This circuit works.
    And voltage output is 1.5V same you read on meter but I look at scope is dc pulse 3Vp-p.

  6. prits

    Helpful ckt.. I am doing this with a 3.7v rechargable battery.. What modifications should i do.. Pls help

  7. i wake up in early morning and start doing the circuit from start i made this on a breadbord i made a new inductor with new wire and ferrite core and then recreate the circuit again and NOW THE CIRCUIT WAS WORKING.Yes i have done misstake but now its working now am so happy..

  8. prits

    Admin pls reply., how to use the ckt with 2 AA cell.pls its urgent

  9. can you give me a circuit which convert 1.5v to 5v using transistor or ic please.

  10. Hi,prits
    Thanks for your feedback.
    This circuit not need use 2 x AA battery. because it can use directly to LED which it need 1.8V to 3V for best.
    It is made for only one battery.

  11. L Lutvian

    can i change conductor 100uH with other component..?

  12. Sarwar

    Hi Prits, You may use 2xAA battery in this circuit by connecting them in parallel.

  13. Peter

    Hello Mr:

    i really faced a problem, i am designning one project

    useing one 18650 battery to support one resistance, so the resistance would heating

    i am try to up the output wattage to 30wattage or 100wattage__the resistence wattage ,

    need to converter the output voltage to 10V or 12V ? the output mA current need to converter 5A ?

    if you can give some advice or i need to choose some ic ?


  14. Paul Baroud

    Dear sirs, hello,

    I am trying to buy components for the high power 6 LED flash light,
    and I never have the good part number.

    Con somebody send to me the complete board ?

    Many thanks, best regards,
    Paul Baroud

  15. Jonathan

    Pls sir does It mean that the more transistors u add to the cct the more current or Voltage you get?

  16. mohsen

    tank you for your site and circuit.

  17. Simon

    Hi I’ve just finished building 6 led torch +1AA battery on a breadboard . Brilliant circuit I will be soldering this one.
    Thanks again for an excellent resource.

  18. Thoson Edimas

    hi sir,will I get more current at output if I add more transistor (s9013)?

  19. Ramesh

    Very Fine Circuits and Material. As a non-Electrical/Electronics Candidate i have a simple question of “How to find the Voltage Requirement of a/any load(May be a LED/Fan/Motor etc)”?

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