Research Cell » Electronics

Voltage Regulator Circuit

genius — Fri, 27 Nov 2009 17:15:26 +0000

Voltage regulation means to prevent the voltage from dropping down or rising above a specific value. A 12 volt regulator circuit will provide exactly 12V under load as well as without load. On the other hand, an un-regulated 12V power supply output voltage with drop under while the load will increase and will rise when not under load. For example, an un-regulated 12V power supply can output 14V when not under load and can drop the voltage to 11V when under 1A load and 10V when under 2A load. This rise and drop of voltage in un-regulated power supplies can sometimes burn sensitive electronics equipments.
I, once, went to market to buy a voltage regulated supply but was amazed to see the cost. I decided to build my own power supply and researched a bit on the internet. My required load was 12V and 1A so I ended up designing the following voltage regulator circuit which is very low cost but at the same time it is efficient.

Voltage Regulator Circuit Diagram

Here goes the parts list.
1. 240V to 15V 1.2A Transformer
2. 4 pieces of IN4001 (You can use a bridge rectifier as well)
3. 220uF 25V Capacitor
4. .1uF 25V Capacitor
5. 7812 IC (Integrated Circuit)
6. A heat sink plate for 7812 IC
7812 is a very good voltage regulator integrated circuit (IC). It is cheap but efficient, that is why I selected it for this regulator circuit. 7812 Pin2 connections are also explained in my regulator circuit diagram. You can see that Pin 1 is input, Pin 2 is Ground (which is often –V) and Pin 3 is output. It is very simple to understand 7812. The 220uF 25V capacitor is used as a buffer to cover frequency gap. The second capacitor is used as an extra filter. IN4001 rectifiers are used to convert AC current into DC current. Transformer is used to convert 240V AC into 15V AC. If you have 110V mains then you can use a 110V AC to 15 AC transformer.
I have successfully used this voltage regulator circuit to power up my ADSL modem. In fact, the ADSL modem was restarted every one hour or so with its original power supply but after I replaced it with this voltage regulator circuit, the modem is never restarted by itself. Any electronic device which requires 12V 1A power can be powered by this circuit so feel free to use it. You can post your questions and comments in the comments section bellow.

7809 Pin and Circuit Diagram

genius — Wed, 04 Nov 2009 15:27:43 +0000

7809 is a voltage regulator integrated circuit(IC) which is widely used in electronic circuits. Voltage regulator circuit can be manually built using parts available in the market but it will take a lot of time to assemble those parts on a PCB. Secondly, the cost of those parts is almost equal to the price of 7809 itself so professionals usually prefer to use 7809 IC instead of making a voltage regulator circuit from scratch. Before you start using 7809, you will need to know about the pin structure of IC 7809. Apparently, it looks like a transistor. It has three pins. For a better understanding, I have given an image of 7809 bellow. Please take a look.

You can easily see the V in and V out pins as well as the ground pin. It is really easy to use 7809 for voltage regulation purposes. I have also included a circuit diagram of 7809 so that you may learn how to use it in a circuit diagram.

7809 Pins

It is wise to use two .1uF capacitors on both input and output sides to filter any ripple or distortion in voltage but it is not necessary. In the image, you can see that 12V are being supplied on the input side of 7809 but the out put side of 7809 is outputting Regulated 9V. As long as the input voltage remains above 9V, output voltage of 7809 will remain smooth and regulated.
Please note that input voltage of 7809 can be up to 23V but under my experience, it is wise to avoid input over 15V. 7809 is claimed to output 9V and almost 1.5A Current but again, I have experienced that we should not put a load over 9V and 1A on it. Since we are using it in power supply, the transfer of power will result in heat output. We will need to use a heat sink with 7809 otherwise this heat can damage it. It is advised to use a 1A fuse on the output side of 7809 and a 1.5A fuse on the input side of 7809 to avoid damage in case of short circuit.

7809 Circuit Diagram

Inverter Circuit Diagram

genius — Mon, 01 Jun 2009 20:14:57 +0000

Power inverter is a very useful device which can convert Low voltage from a DC source to high voltage AC. The most common power inverter is 12V to 240V inverter. Perhaps that is because 12V batteries are common. This type of power inverter usually draws current from a DC battery. This battery should be able to provide a high flow of electric current. Normally lead acid batteries can server this purpose well. This current is then converted to 240V square wave alternative current so that we may empower those electric appliances which work on 240V instead of 12V. Inverter falls in the category of expensive devices so many people don’t buy them even they need them. What if I tell you how to build an inverter yourself?

I remember when I build my first inverter, I was very happy and I invited a lot of friends to see my homemade inverter. I am sure you will feel the same. Before you start building this inverter circuit diagram, I want to mention that this circuit involves 240V and 500W which can be fatal. You should take all security precautions before building this circuit. Preferably use electricity protective gloves and try not to play with the inverter circuit when it is operational. You will need little to medium knowledge of electronics in order to build this circuit. Alright, let us get to work. There are a lot of inverter circuit diagrams available online; some of them are complex and others are low performance. I have researched on a lot of them but in the end, I designed my own inverter circuit which is comparable to any professionally made inverter but still is simple enough for you to try. Here is the inverter circuit diagram:

Inverter Circuit Diagram

It took me less than $100 to complete this circuit.

You will need the following parts.

2 Resisters 470 Ohm ¼ Watt
3 Resisters 22 Ohm 1 Watt
1 Variable resister 10K
1 Capacitor1uf
1 Capacitor 220uf
1 Zener diode 8.2V
1 IC CD4047
1 IC 7809
1 Transformer 12+12/240 (500W)
2 Transistors D313
12 Power Transistors TIP35C (make two pairs of 6 transistors each connected in parallel)
2 Heat sinks to fit power transistors
Some wiring wire (for connections)
A wiro-board (To build circuit on)
A 12V battery of 12V power supply for testing purposes

There is only one variable resistance in this circuit diagram which is used to adjust frequency of 240V AC output current. You should have a frequency meter to adjust this frequency of 50HZ to 60HZ as per your requirement. Please do not power up any device with your inverter before frequency adjustment because a wrong AC frequency can burn your equipment as well as your inverter.

I have used a two stage regulated power supply to avoid frequency changes with the drop of battery voltage. First stage is 7809 which is a standalone voltage regulator. It converts 12V DC to 9V DC. Then we have used a 22 Ohm resistor and then a zener diode of 8.2V which forces current to stay at 8.2V. The 22 Ohm resistor is there just to aid zener diode. The output frequency of this inverter circuit is square wave so it is not best to power up inductive loads so use it at your own risk. However I do power up fans at home using this inverter and I never had any problems other than a little decrease in fan speed and addition of a little noise. If you have any questions, please use the comment box bellow.

Tango T600 Electric Car

alex — Tue, 12 May 2009 13:58:28 +0000

Tango t600 is a unique electric car. It is unique due to many factors. It has a thin body structure just like motorbikes. The only difference is, it has four wheels and a covered structure. Tango t600 electric car is capable of having two passengers sitting comfortably. Its thinness is its advantage as well as disadvantage depending upon personal needs. Tango t600 can change lanes quickly and can by pass other cars even through lane gaps. This electric car has a luxury leather lined interior. The car is powered by batteries and two DC motors. These motors are fit in the bottom of the car to assist the electric car balance. Batteries have the biggest share in electric cars total weight. The initial weight of Tango t600 is 1360 Kg and two third of the weight is caused by powerful batteries. Electric car can be fully charged in almost 3 hours or less. A quick charge mode can charge 80% of batteries in 10 minutes. Once fully charged, Tango t600 can travel 96 to 128km depending upon the weight it is carrying. The batteries used are lead acid but company plans to use LI-Ion batteries in future. Tango t600 has a top speed of 240km/h which is very good for an electronic car. Car can cover first quarter mile just in 12 seconds. It can achieve a speed of 96km/h in 4 seconds only. It can further reach 193km/h just within 12 seconds.
Tango car can change lanes just like a motorcycle so it has a lot of driving advantages during rush hours and heavy traffic. However, it is a lot safer than a motorbike. You can drive in any weather and can also carry a smart amount of cargo with you. It is easy to park Tango t600 any where due to its small width. Although it seems to have less balance than normal shaped cars, but Tango t600 has a weight concentration in its low center which makes is extremely safe even on high speeds. Especially when 2000 lbs batteries are fit in its floor, it can be driven just like the sports cars. Other models of this car are Tango t200 and Tango t100. Being an electric car, Tango is low noise which makes it extra comfortable and environment friendly.

How to purchase a Solar Panel?

alex — Thu, 02 Apr 2009 13:51:17 +0000

The purpose of a solar cell is just like a normal battery cell which you purchase from the market except that it generated energy when exposed to sunlight. Yes! It is that simple. You just need to purchase a solar cell from the market for a specific volt rating and put it in the sunlight and it will output DC voltage.
If you want to purchase a solar panel then you must know about following terms.
Efficiency: It is the most important factor of a Solar Cell. Take a survey of the whole market and make a list of the prices and efficiency. You should purchase that solar cell which has the highest efficiency and still falls in your budget.
Cost to Energy Ratio: This is the modern term which you might not find on all solar cells. However if you find it, make sure that the ration is as higher as you can afford.
Life Time: Old solar cells have less life span as compared to modern solar cells. Make sure that the solar cell you are purchasing has at least 20 years of life.
Watt: This is the term you are already familiar with; you can decide how many watts you need as per your electric consumption.
Volts: Normally you will need a 12v solar panel. However make sure that the solar cell you are purchasing has your required volts output.
Suggestion: I suggest you to use the solar cell with a chargeable battery and then directly with your appliances. For example if you have a 12 volts solar panel, just connect it with a rechargeable battery and then run 12 volts devices on this instead of purchasing an inverter to convert it to 110v or 220v. It will result in a double loss, a loss of money as well as a loss of power. Inverters waste a lot of electricity during voltage conversion. You can easily find 12 volts fans, cell phone chargers, laptop chargers etc within your market.
Just to explain the functionality a bit, Light is pure form of energy. Sun, which is the greatest energy holding object in our solar system, emits a lot of energy towards earth in the form of light and radiation. When this light hits a solar cell, it is absorbed by semiconducting layer of that solar cell. This extra amount of energy causes a flow of electrons but those electrons are only allowed to move in a single direction. This also cause positive charge on the opposite direction termed as holes. This results in a potential difference between both ends which is called voltage or electricity in simple words