When I was 8 that was 53yrs ago & was pulling old valve radios apart to see how they worked. this eventualy led to repairing things electronic (at 61 Yrs still pull things apart to salvage components) Very encouriging to see a young lad interested. Daryl

 

ok, what the use of so many op-amp Ic??

 

What is MOV's, & why they areused??
i have seen in video.

 

Hello,

A MOV (Metal Oxide Varistor) is a special kind of resistor.
The value changes (becomes lower) when the voltage goes over a certain level.
http://en.wikipedia.org/wiki/Varistor

Bertus

 

How to know on the voltage rating of them??

 

Hello,

Here are two links with a lot of information on the ratings of the MOV's:
http://www.iaei.org/magazine/?p=2545
http://www.koaspeer.com/circuit_protection.asp?part=14

Bertus

 

The voltage that a MOV breaks down is printed on it. It is part of its part number (including its size) so look at the description in its datasheet.

Without looking at a datasheet, I guess the printing on a MOV is like this:

 

I just had an idea, could a varistor be used as an oscillator, just hooking it to high enough voltage for it to break, but with a suitable series resistor and some small cap in parallel?

 

Hello,

@kubeek,
The MOV's are not designed for fast multiple acting.
If you want a relaxation oscillator, you better use an UJT or PUT.

Bertus

 

About 50 years ago I used neon light bulbs as high voltage oscillators.
About 45 years ago I used UJTs and PUTs.
Then I discovered Cmos logic ICs.

 

i have seen this glass tubes many time, pls tell name of it in this circuit...?

This looks like a low power stereo amplifier. The big tube over to the right is a rectifier for the power supply. The small tubes at the front are a pre-amplifier stage (probably either 12AX7A or 12AU7A twin triodes). The taller tubes at the back are likely the output stage and probably drive the output transformers in a push-pull fashion.

This would fetch a small fortune if sold in working condition in North America. Probably around 16,000 rupees.

All just guessing though.

Edit: Ahhh, on closer inspection the pre-amp tubes are 6EU7 units. Very similar spec wise to the 12AU7 except with a 6-volt heater rather than a 12-volt heater.

 

ok, what the use of so many op-amp Ic??

Op-amps are the basic building block of modern linear electronics design. They can be used in literally thousands of different ways. Oscillators, servo amplifiers, integrators, differentiators, comparators, switches, summing, mixing, etc... Without a schematic of the UPS, it would be difficult to tell you to what specific use they were put.

 

Don't know why everyone here tolerate all of those stupid and dumb questions. Tell you honestly, in my working place there is alot of indians and they were all lier and pretending that they know everything specially those who are electronics engineer. It is tested and proven. What else? they just keep on talking things that in fact they don't really know in short they are just good only in talking ****. Sorry for the words but it is really shameful that you asked those simple questions without first trying your best to understand it. Like the one who started this thread, I saw alot of post from him which are totally shameful and he don't want to make any effort. "you better use the ladder, raher than taking elevator"

 

Hello,

@newbies_hobbyist
There are NO stupid questions.
There can be stupid replies.
How did you start yourself?

Bertus

 

He's OK once you get used to him.

The 'adults' who are holding jobs in fields in which they are not well versed, IS a problem in some places. It fixes itself over time through market and business forces. Meaning they get fired or the company that hired them goes broke or closes.

 

Hello,

@newbies_hobbyist
There are NO stupid questions.
There can be stupid replies.
How did you start yourself?

Bertus

Yeah right, I started as newbie but not as bad as him. I used every reference book I have, read it and try to understand it. If I don't really understand it then I ask other's opinion. What I'm saying is atleast give some effort. let me ask you too, you started as newbie as well but do you see yourself with him when you are a newbie?

 

Hello,

I started some 40 years ago with the EE boxes from philips.
http://ee.old.no/

RRITESH also has the barrier of the language to overcome.
That makes it also some harder to have the conversations with us.
We are here to help EVERYBODY.
Please keep that in mind too.

Bertus

 

yeah of course everyone should help the other those who don't understand much about electronics. In fact I still consider myself as a newbie that is why I keep on reading forums in this site and I love to see the very helpful post and replies of every member here. when it comes to language barrier, I'm not as good as those who are really western people beause I am an asian too but I didn't let it to stop me from understanding and learning electronics. anyway I just get carried away only.

 

I don't Know the difference in these transistor, pls. give some detail of it??

 

here are the transistor.