RC India

using sanwa  multimeter, please can some body guide me for following


1. how to use this function on multimeter , should i directly plug in the three pins of transitor in this socket in first pic,where do  i have to put the dial(mid wheel of the multimeter) , on buzer or on diode symmbol, or on any other ()

2. are these diodes ,how can i check these??where to put the dial(mid wheel of the multimeter)

please guide .brown in colour and black in colour ..

Vineet, i do not have any clear idea about your knowledge in Electronics.to enter in Electronic circuits, we need some basic knowledge about basic components, and its internal structure. for example, if we want to check a transistor, with multi meter, we must know, about the transistor, as it's pin configuration, internal structure, means, may P N P, or N P N, internally protected, or with internal diodes, is a Darlinton pair or not..many..so, its too simple to get a data sheet, of a transistor, from the World transistor data Equivalents, or from internet. after referring the structure and pin configuration, like Emitter, Base, Collector, look for the Hfe reading in the data sheet. then turn your multi meter in to hfe mode, and insert the device in to the slot, by ensuring the base, Emitter and collector. you can see many holes in twin layer of slots, marked as P N P, or N P N, and as Base, Emitter and Collector. read Hfe  according to the spec sheet.if it is within the feasible limit, the device will be OK..you can also check the transistors and MOSFETs with probes in ohms mode. please do not try to check the components on the PCB.some other components will interact, so you never get the actual reading about the respective components. :thumbsup:

respectd roopesh sir
i have a keen intrest in electronics. But only know about basics.
Just test a transistor and it displays some value like 181 so that must be hfe value of that transistor right,so acording to you it must be equals to  the vale to its hfe sheet  which i cn get it from intrnet.tel me did i get you well or wrong

Vineet,

For measuring the Hfe set the dial to point HFE and insert the legs of the transistor in the socket. You should know which is the base, collector and emitter. Its highly recommended to get the datasheet of the device that you use than measuring Hfe as this value varies quite a lot from one unit to other.

On the second pic the components that you have pointed out are capacitors. There is no way of telling its value unless you measure it.

Hope this helps.

-Ismail

respected izmile sir,


the point is how can i measure the value of these capacitors , how do i know they are working right or faulty ,

they are BROWN in colour and if you take a closer look the you will find that some of are  BLACK in colour and they all have no . on them like 130 ,530, very tiny ,

i think they are known as diodes the black one  , or they both are ceramic capacitors,

Try for Datasheet the following sites :
http://www.datasheetarchive.com
http://www.alldatasheet.com
http://www.datasheetcatalog.com
http://www.datasheet4u.net

Another thing vineet, Dont rely on the shown data. The hfe or beta also depends on where your device operating point is. You can see that most of cheap multimeters shows hfe as large, but in circuit you will find less, specially for signal transistor, and in Power transistor, the thing happens reverse (Looking strenge, but it happens to CHEAP MULTIMETERS.)

For, hfe, just place in breadboard, connect +Vcc to base with 1M and collector to +Vcc with 10k resistance and emitter to gnd . Measure the base and collector voltage (Any DMM, DC voltage range shows accurate ;) ). Then just calculate hfe. Now replace base resistance with 10k and collector resistance with 100 Ohm. and recalculate hfe.

You will see the change in hfe for change of operating point and power loading. Use +3 to +5 volt. Also for PNP transistors, +Vcc will be replaced with -Vcc.

All this change will be observed due to minority carriers and internal temperature of the chip which is again depend on the power dissipation.

So, showing value, you can declare that the transistor is not open or short.

Thats it.

Vineet, another thing i request you, electronics is very easy if you not jumped some chapter.

I prefer A. P. Malvino's "Electrinic Principle" Third Edition (higher editions are bulky in volume) for learning electronics SIMPLY AND CORRECTLY with step by step design. there are some well known Indian books where I see basic defects in circuit specially DC biasing in Oscillation Chapter and in other places exceeding power capacity.

http://www.talkingelectronics.com is another online correct and simple study material.

I saw almost 15 years ago, an vary thin book named "FM RECEIVERS" by V. V. Sampathkumer, but not find that book any more in Kolkata and still searching for that book and requests all if anyone have a copy.

May be I shifted from topic but this is the all I experienced from my life.

Thanks

 :bow:

respected kalyan sir,  i was expecting you from the first time i post this thread ,
basically by following the above step w can know whether the above transistor is short or not ,

but how about those brown and black tiny parts known as  capacitor how can i check them.

i will try to arrange  books .
 

Kalyan, with a 5V supply and a 100 ohm collector load, the DUT could well draw a maximum of 50 mA. That would destroy a small signal device. Would rely on your vast experience to correct me if I am wrong.

And Vineet, why would you want/need to know the hfe of a device? All you would normally require - unless you want to design your own circuits - is whether the device is open, shorted or leaky. For bipolar transistors a simple test using an ohmmeter would suffice.

dear  sushil sir


i know that , i want use that port of the multimeter ( in picture 1),   also want to know how can we check them through that.

and last i love to have a knowledge of electronics

Vineet. That is good. But do remember that in the real world, how one makes practical use of theory is much more important. Take geometry for instance. It is certainly good to know , from various theorems, how areas can be measured etc. How we put that to use is the relevant thing.

Also, nowadays, most (including the board shown) circuits use SMD components. Without the right equipment, you would find it very difficult to remove a transistor without damage to the board. And if you did, it would not be practical to wire leads to it to be able to insert into the hfe socket on your meter!

QED!

Please do not take this as discouraging in any way. Keep up your interest!

Vineet,

I would say its better to work with leaded components than surface mount (like the ones in the pictures you posted). Try to get a few BC107 transistors. The datasheet should be available on the net. Insert the legs of the BC107 into your meter's socket and check its HFE. Now, try a couple of other BC107 transistors you would be surprised to see the variance in HFE. The datasheet shows this value in min/max and they vary quite a lot.

The black components are "mostly" resistors. The number on them denote the resistance value. But these marking could vary for each manufacturer. I always test the resistors with a proper meter.

The brown ones are "mostly" capacitors. The will be no markings on them. The only way is to measure them by using a capaciatance bridge. Your multimeter may not be very helpful as these components may be in nF or pF range.

And lastly, if you are after electronics knowledge, please read the literature - "Art of electronics", "Electronic Devices by Robert Boylstead".. There are may good books out there. Magazines like "Electronics for you" are also good.. Well, they were good 10 years before but now its more of ads than design ideas.. Anyway, do visit your local library and dust off those old electronics books if any.. I think old electronics texts give you lot of fundamental concepts than the new ones...

Good luck.

Vineet,
Again a hidden information from me. My all Mobos (7 incl. 2 month aged intel ATOM 410) gone down due to High humid weather in Kolkata for last few days, and for my MOM, who closes the windows of my room to protect from rain, but makes humid as saturated air confined within room and keep stuffy 18 hours. I am posting making one AMD Mobo +1GB RAM Alive. Even my loving 1TB 6 month aged HDD started problem, but survived.

The strange news is that, High humid weathers damages the Mobo Capacitors (Not bursted or puffed) and hot air gun (SMD rework-station) energizes one by one. And the most surprising news is that this occurs during changing of average humidity of weather insted constant humid weather. The capacitors, are can be checked only drawing from PCBs, but please use 2 os 6 watt soldering iron or SMD re-workstation with stainless steel tweezers to open from PCBs. Then only you can check shorted or not.

Another strange thing is that most time these faulty capacitors damages Transistors/ MOSs/ IC output stage for that capacitor replacement is not the solution. This things happens in Cell phones too and if you want more life of your cellphone, just avoid to keep within dress/pocket if you are not in AC environment (Less BMR and less sweating resulting less humidity) >:D .

Lastly,  (:|~
Ib = (5-.7)/10K = 430uA.

Let, Beta/hfe = 100  -  -  -  - Signal Transistor, possibly in saturate mode as Rb/Rc=100 < beta
Ic = 100 x 430uA = 43mA,
 VRc = 100*.043 = 4.3 volt,
 W tr = 0.7 x .043 = 30mWatt

Let Beta/hfe = 50   -  --  -  - Power Transistor
Ic = 50 x 430uA = 21.5mA,
VRc = 100 x .0215 = 2.15 Volt
W Tr = (5-2.15) x .0215 = 61mW

Yes, the 1 rupee transistor may be blown off if it be 547/548B. But checking with TO220 package as shown in Pic above (Like 2233, 13005) it would not blow.

Simply trick is here. 100 Ohm resistance in 5 volt draw 0.25 watt Max, and The transistor can consume maximum 0.25/2 watt = .125 watt or 125 milli watt as per Maximum power transfer theorem.
Now, at Maximum power point, Vc = 2.5, Ic = 2.5/100 A = .025A = 25mA
Ib = 430uA = .43mA
hfe = 58 (Absard for signal transistor).

So, the transistor should not blow at any case. 33K and 100E do best for signal transistor.

Rb/Rc = 2*hfe gives best result and sets Q point at class A operation mode.

I May be wrong as I never score 100/100 in math and may be excused. All will be easier than my explanation if you read the book said earlier. Canvasing? May be, I am a grate fan of Malvino for simplicity.

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Moral : Keep window open as maximum as possible. (for both knowledge and room).
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kalyan sir the data you always provide  is very intresting , but   only get 10 percent of it , i really want to know tits and bits of every thing you provide, i will try to arrange a book for me , lot of suggestion around here ,  but for starting i just want a book with basics.

you are right sir , i have damaged many smd circut , but for now i am using 10 w iron and smd station some where needed not much ,  it is helping me to overcome the problem , i think most of the smd are use and throw not .
i just pruchased liquid aluminum flux, smallest gage solder wire,desoldering wire, two iron 10 w and 25w and a bottle of flux removal few days ago they are helping too much.

thanks for the justification on  both of them , thats what i was looking for , but now  is there no way of checking them .and also some body told me that we cannot check ic as they can only check on board, if they are working they are fine if not they are they are useless.