Every electronic circuit, project or gadget like our mobile phone or the speakers that we use, require electrical power to function. We can draw this required electrical power from our mains outlet using a power supply. When we want mobility and freedom from wires, we have to use portable power house. These are DC power sources and we call it a Battery. There are many types of batteries and there are literally infinite appliances which uses batteries of different types. Our TV remote, Wall-Clock, wrist watch, cars, laptop, mobiles batteries are everywhere. Battery provides a mobile voltage source. Depending upon our requirement we chose a battery which fits our requirement and our budget. e-vidya comes with a 9V Battery which is available everywhere and most easy to use. The household battery which we also call as pencil cell used in tv remote is small one and gives 1.5V of DC voltage. The DC power source is denoted in circuit diagram by a special symbol as shown below

battery symbol

Anode represents positive terminal of battery and cathode represents the negative terminal of battery. During building various circuits, we have to take extreme precaution that we should not connect it wrong otherwise; it may cause severe problems to our circuit. So take care while connecting the battery to any circuit. The 9v Battery provided, has a clip showing red wire for anode and black wire for cathode. 9v battery looks like this



How Battery Works?

So what actually is a Battery? It is a combination of two or more electrochemical cells in which stored chemical energy is converted into electrical energy. Each cell consists of two half cells connected in series through an electrolytic solution. One half cell houses the Anode to which the positive ions migrate from the Electrolyte and the other houses the Cathode to which the negative ones drift. The two cells are may be connected via a specific structure allowing ions (charged particles) to flow.


Typs of Batteries

Apart from these 9v Batteries, below are some common types of batteries we use along with pictures and their rated voltage and applications where they are used

Name Picture Specifications Usage
Pencil CellGeneral CellAA Type  AA vs AAA 1.5 VoltLightweight Low currentNon-Rechargable Remote Control Battery, Toys, general Purpose
Pencil CellGeneral CellAAAType  AA vs AAA 1.5 VoltLightweight and Low CurrentNon-Rechargable Remote Control Battery, Toys, general Purpose
Lead-Acid Batery  lead-acid battery 12v, 6v Heavy and High Current CapacityRechargable Emergency Lights, Solar LampsEmergency Fans, Computer UPS
Acid Filled Battery  exide big battery 12v, 24v, Very Heavy, Very High CurrentRechargable Vehicles, Bikes, Cars, Inverters
Special BatteriesLi-Ion  lithium-ion-battery 3.7v Each CellHigh CurrentRechargable Mobile Phones, Cordless PhonesLaptops
Special BatteriesNi-Mh  Ni-Mh Battery 1.2vRechargable Mobiles
Special BatteriesNi-Cd  ni-cd battery 1.2v High Current Small SizeRechargable Mobiles
Battery Pack  battery pack Ni-mh, Ni-CD or Li-Ion battery Pack combined for higher voltageRechargable Mobiles, Robotics