Please Please, i need urgent help, regarding this circuit

[sajidraheem]

I'm a srudent of BS Telecom Engineering.
I have done a project of controlling home appliances using Computer.

I use LED's to show the appliances, to control home applinace no. 1 means lighting the 1st LED. i used 7 LED's and implemented it using 7 segment display.

Now our instructor is asking me, to write down all the changes/modifications, required to implement this breadboard circuit to real world. Means, to control the appliances actually, not the LED's

Please I have the exam the day after tomorrow. I'll be grateful if u kindly help me regarding this.

sajidraheem@hotmail.com

Thanks

 

[The Mad Professor]

Getting the electrical power to run the appliance ...
https://news.bbc.co.uk/1/hi/business/4802248.stm

 

[sajidraheem]

sorry sir.
i didnt find anything relevant to my circuit at that link]

I just wanted to know, if we want to put an appliance at the place of LED
, what changes are required in the circuit? I am using a hex to 7 segment decoder IC and Buffers also in my crkt.

 

[sajidraheem]

He told me that surely my circuit can, really it can work in real world, but some changes are required. I told his that may be transformers are required, to step up the power, but he said no, something else.

I dont know wut to do..

 

[dknguyen]

People are just a little apathetic when you come online asking for an answer to your homework question.

Do this: Take your circuit and pretend it is actually in an appliance. What would go wrong? FOr example, if you plugged your circuit into the wall, would it explode because it's not designed to run off of the wall power? It's only something you can figure out for yourself since we don't have the circuit, and even then it's probably not enough because in practice we need the actual circuit sitting in front of us. Go through the actions of using your circuit in real life and find out reasons that might not let it work. It's impossible for us here to do it, especially since we know nothing about it.

The differences between your house and the lab are the differences that will not let the circuit work. Find them.

Transformers ONLY work on AC voltages (meaning it is highly unlikely you can use them directly with ICs). Transformers DO NOT STEP UP POWER. They don't make power magically come from nowhere. Transformers can only output less power than what was put into them. They reduce voltage and increase current, or they reduce current and increase voltage. Appliances need enough voltage AND current to run = more power. You can have the same amount of power in the form of less current and more voltage or more current and less voltage. That's why your prof said no you cannot use a transformer to step up power. Power has to come from somewhere. You can use a transformer step up voltage or current, but not both at the same time.

 

[sajidraheem]

I am using a 9 V battery to drive the LED's and IC's. so how can i control 220 V appliance???

and if i use a 220v source then will my IC's work, which only operate on 5V

Actually i m in my very early semesters, i dont know this basic thing.

 

[dknguyen]

It's pretty obvious isnt it? Didn't you ever wonder why you didnt just plug your circuit into the wall but were using a 9V battery instead? 220VAC, note the AC part of it. Your electronics can't run off of a high voltage like 220V. Not only that, they can't run off of AC. On the other hand, you don't really expect to power your circuit from a 9V battery when the there is a huge power supply available from the wall do you? Hmm...so how can you make your circuit run off of the wall power?

Also, remember the appliances are BIG and ICs are SMALL. So you can't control it directly with the MCU. YOu need some kind of driver or amplifier to do it. That's also something you would have concluded if you had just sat down and thought about.

It's starting to sound like you realize things won't work, but just won't think them through or try to come up with solutions to them. If you suspect something won't work, it probably won't.

 

[sajidraheem]

I told the same thing to my instructor that our IC's cant work for 220V AC
this ckt will not work for real world appliances but he said, it does.
i am still sticked to my point that IC's are designed to work at 5V DC and Appliances for 220 V AC

 

[ClydeCrashKop]

If you have enough power to operate 7 LEDs, you can operate 7 transistors or small relays. Either one can operate big relays. Big relays can operate anything.

 

[dknguyen]

A driver is a circuit that allows one small signal to control a much larger signal.

I'm not saying anything more other than this. If you see something that will not cause your circuit to work...FIX IT. WORK AROUND IT. You know what's wrong with it, so start looking for solutions. Don't just keep repeating the problem until you get an answer.

 

[Styx]

I told the same thing to my instructor that our IC's cant work for 220V AC
this ckt will not work for real world appliances but he said, it does.
i am still sticked to my point that IC's are designed to work at 5V DC and Appliances for 220 V AC

no IC's will run off 220V AC,
There are cct's yes but there is alot of stepping down of voltage rails to get the 220VAC (which is around 310V DC rectified)

this sounds like homework!
without a cct we do not know IF you have relevant components for it to run off of 220VAC

an LED can run off 220VAC with a big enough resistor

 

[sajidraheem]

My Actual Circuit is like this:

http://www.geocities.com/sajidraheem/4.gif

In the place of a, b, c, d, e, f, g pins of 7 segment disp i have used 7 LED's

I'm trying to work the problem out, but still if someone can help, i'll b grateful

 

[ClydeCrashKop]

Do you understand relays?

 

[sajidraheem]

No i dont

i told u, i am in very early semesters of my engineering, havent studied the course of electronic ckts yet..

can u give me the idea??

 

[ParkingLotLust]

A relay is like an electronically controlled switch. A current (electricity) flows through a coil that makes the switch turn on in a sense. You would connect the coil of a relay to a transistor (and the transistor in place of the LED) and whenever the LED would turn on, instead the relay would turn on, turning on the appliance. As for running your circuit off 220v, you would need a 'power supply' of sorts. Basically a transformer hooked to a bridge rectifier and a voltage regulator, and some filtering caps. Do a google search for it, they arent hard to find.

 

[ClydeCrashKop]

A relay is an electromagnetic switch. Your 5v can operate a small one that is maybe strong enough to run a light bulb or to turn on a bigger relay that can operate a water heater.

 

[sajidraheem]

Thanks Alott All of u Sir.
I got it
Like relay is going to switch on our 220 V while it itself works on small voltage, so working like a switch. got it
Thanks

 

[naveed7]

hello sajidraheem..
i am naveed ,i am doing BS electrical engg ,,i am intersting ur project,,i am also in final year ..pls u send to me ur project detail and all documentation,,.on email..
naveedp@gmail.com
pls soon replay..
best regards.......

 

[jackemery]

jackemery The Amazing Giant

I am using a 9 V battery to drive the LED's and IC's. so how can i control 220 V appliance???

and if i use a 220v source then will my IC's work, which only operate on 5V

Actually i m in my very early semesters, i dont know this basic thing.

Use a 5-9v Relay ( low coil current ) that the Contacts will handle 220v open or closed. It Works. May use a Relay with more than one on/off open/closed contacts rated at amps required at 220v. www.amazinggiant.com jackemery

 

[naveed7]

help me

hello sajidraheem..
i am naveed ,i am doing BS electrical engg ,,i am intersting ur project,,i am also in final year ..pls u send to me ur project detail and all documentation,,.on email..
naveedp@gmail.com
pls soon replay..
best regards.......