The idea came to me when i was ready to replace a battery cell in my alarm clock next to my bed. Even i am using the last 5 years only rechargeable batteries of the most types i considered how many battery cells people around the world throw away in a simple move like that i did now.....How meny disposed battery cells thrown away in each household? Who knows? But what if we had a rechargeable system to recharge batteries when the device is connected to an outlet and when we will need the battery (In a black out) this will continue working the device.So first we will have power continuity, second we will save money buying and dispose all the dead batteries, and third under normal conditions we can rechargeable any type of battery we like. My next question to my self was that this kind of circuit must be simple, cheap, realible, and easy convertible to recharge any battery cell and giving power to a device at the same time. SimpleEhhh????
So i tried to recall my studies from university and i reminded a very simple circuit which actually recalls all the science of electricity and every 1st year stuedent knows well.
Materials..... Cheap and Easy
>>4 diodes of 1N 4001 type for making the bridge which conncects to the transformer
>>a transformer 2x6 if you want to recharge batteries from1-6VDC or 2x12 for devices up to 12VDC (input 220VAC europe output 2x3,2x6,2x12 choose your one)
>>a 1000uF Capacitor, using it as a filter and elevator of the power
>>a Relay (6VDC if you will give power from 1-6VDC or a 12VDC if you like to recharge a 12VDC battery)
>>a resistor of 33 or 39 Ohm /5W (5W is ideal because the resistor cool down faster)
>>a diode of BY251
>>2 rca female for chassis
>>2 rca male
>>a prototype card or a perforated card, no PCB needed
>>a nice box for the battery recharging docking station appx12cm X 5cm X 3 cm ( in this box you will try to fit a transformer, the basic circuit , cables, the battery nest and your spirit! :D
All materials costed to me 12euro (15USD) The most expensive is the transformer.
Lets go now at the circuit design and i will explain to you....
Step 1: Explaining of the Circuit
first of all the circuit is well separated is two sections the power supply on the left (green line) with the battery pack and the outline with the purple line
We take the transformer (220V europe make the calculations over Atlantic reader) and we connect it in a formation of diodes called bridge.This circuit is what a first year student learns and remember it for ever. Its the simplest circuit to achieve best reults, cheap and realible.Ok, if u like to transform from AC to AC again then the circuit remains the same u change the diodes of type 4402, 4403, 4002, ofcourse the transformer and the appropriate relay working in AC. The capacitor of 1000uF value is a filter and a choke to elevate the power. Connect the diodes to the capacitor and then this one at the line of the relay. Then the + pole of the device gets to the switch of the relay. At the + pole of the device we attach a diode or a BY251 and a resistor 33Ohm of 5 Watts (we prefer 5watts so the resistor isn't get hot when it works and cools down faster)
You will not need any PCB. Take a protorype or better a perforated card and just place the materials and do the connections. No particular attention needed (of course take all the precautions when using high voltage such as 220VDC are able to fry you in seconds and send next to your anchestors for ever)
from the + and - we will take line and we will drive it to 2 RCA female (chassis) The one male RCA connected here goes to the charge the battery and the other goes at the device where we will place a fake battery