Using the Trimmer/POT/Trimpot (lol) the user can adjust to make the RED LED light-up when ANY battey OR battery-pack is connected to the power terminals ! Operating voltage range is 3V-12V

Before i start, this is my 1st ever PCB i will etch, only started learning electronics beginning of 2012 !!

Also FULL credit goes to daftmike on the website below for making the initial circuit, all i did was to copy it into Fritzing to enable me to make a tiny PCB out of it!!

LED LOW BATTERY INDICATOR

P.S - If anyone can make this EVEN-SMALLER to be fit onto the SMALLEST-POSSIBLE PCB, Please please please feel free to do so as i'm an absolute beginner with electronics & i would be most-grateful if you could share it too !!!

This Circuit is made with the most COMMONLY available & CHEAPEST components possible so anyone can make as many as they want without fear of it costing stupid amounts of money, all from home!

(ive also included a bit more info on the components that i used, all-in-all i used only 6 resistors, 5 transistors, one Trimmer & 2 LED's & a small piece of Single-Sided PCB!)

Ingredients:

Resistors (All 0.25 watts, 5%, 300 volts MAX) 10K x 4 1K x 2

Transistors (General Purpose) BC547B x 5 Condition; MAX Ratings; collector-base voltage 50 V collector-emitter voltage 45 V emitter-base voltage 6 V collector current 100 mA peak collector current 200 mA IBM peak base current 100 mA

LED's:(i used 3mm LED's because they were low power) Green LED x 1 Red LED x 1

Trimmer/POT/Trimpot: 10K x 1 Resistance Tolerance:± 25% Power Rating:500mW Voltage Rating:250V Resistor Element Material:Cermet No. of Turns:1 single turn

PCB Size to Cut: (all sizes are in mm) 18.6 (Width) x 45.1 (Height)

{Smallest possible Size !!!}

StripBoard Size Used to Prototype: 25 (Width) x 65 (Height)

Lastly, Fritzing IS AWESOME & Thanks to everyone making it so simple to use and much better than anything out there EVER !!!

(also if anyone could upload a 556 dual timer IC so we can add it into Fritzing, i and thousands of people would be grateful as i cant at the moment, knowledge is still very basic & many thanks in advance!!!)

Main Stripboard Picture is also from daftmike, if anyone makes this circuit, a thanks should go to his post in the above link to his instructions, just to be cool !!!