How can I check TL431 to know it is damaged or not?

[alec_t]

A NiCd battery would normally be charged at a constant current, not a fixed voltage. I suggest you visit www.batteryuniversity.com for guidance.

 

[Willen]

Sigh

I believe Basics are the problem with this kind of stuff.

If the person you are trying to teach does not know the fundamental rules.....you will never ever get anywhere.
A hard road for any teacher to travel.

Just knowing Ohms Law for example would be a solid start for anyone REALLY interested in Electronics.

I am not getting involved here.

But yes, I had to chirp as usual. Solid Basics are the secret. Ohms Law is ingrained in my Brain. V over R X I. Many people sit and look amazed when my little brain can calculate stuff....and the answer is given to them without the use of a Calculator.

Only the Basics. I can make that Formula talk( if it could) because I know it so well.

Regards,
tvtech

Not all are like you man! I am not a person from electronics field, I had finished university but not with electronics. It is my most interesting hobby. I think you forgot your starting phase.

I don't know what is your intention but it feels so bad if one tried to learn another strange subject but expert laugh or insult at learner. If I am a very wrong person here (because I am very basic at electronics) then dear moderators, why don't you delete my each post???

 

[tvtech]

Not all are like you man! I am not a person from electronics field, I had finished university but not with electronics. It is my most interesting hobby. I think you forgot your starting phase.

I don't know what is your intention but it feels so bad if one tried to learn another strange subject but expert laugh or insult at learner. If I am a very wrong person here (because I am very basic at electronics) then dear moderators, why don't you delete my each post???

Hello Willen

I never laugh at people trying to learn Electronics. I still have lot's to learn too. I simply stated the obvious in that Basics are VERY important in order for things to make sense.

Regards,
tvtech

 

[Willen]

Hello Willen

I never laugh at people trying to learn Electronics. I still have lot's to learn too. I simply stated the obvious in that Basics are VERY important in order for things to make sense.

Regards,
tvtech

Thank you dear tvtech, that is why each simpler Ohm's law makes me so happy when I find it on real circuit. It's nice to learn here, because here are very experience members like you, MrAl, alec-t, audioguru and other more.... Thank you lot to them!!!! Nice guys!

 

[tvtech]

Thank you dear tvtech, that is why each simpler Ohm's law makes me so happy when I find it on real circuit. It's nice to learn here, because here are very experience members like you, MrAl, alec-t, audioguru and other more.... Thank you lot to them!!!! Nice guys!

LOL I am not a dear and all. And Ohms Law is Ohms Law......no simpler versions available yet as far as I know....

Glad you like the all the long time Members like MrAl,alec-t,audioguru as well. I like them all too

When they speak, I listen very closely. So I can learn too.

My field is CRT TV. Know it well. Other than that , I listen and learn here. Love it .

Best Regards,
tvtech

 

[tvtech]

Thank you dear tvtech, that is why each simpler Ohm's law makes me so happy when I find it on real circuit. It's nice to learn here, because here are very experience members like you, MrAl, alec-t, audioguru and other more.... Thank you lot to them!!!! Nice guys!

And of course....you have some of the best people available anywhere to spend the precious time.

This Forum does not dream up answers. It factually provides them.

Eric takes care of Digital and Spice (at the least). Nigel other stuff. And Ian is also onto Digital. Don't mean to Crap anybody out but treating this place as a learning ground for people that will not understand that we do not have a bunch of Wankers involved here is a No Go.. Every single piece of advise given is good to go.

Me, myself, as a long time CRT tech will not try and be clever in the Digital side of things...because I would make an absolute fool of myself.

This Forum is the culmination of many people who are specialists in what they do well. And hence my feelings about this...

Ag.. you know how I feel Guys

Think about it.

tvtech

 

[Willen]

LOL I am not a dear and all. And Ohms Law is Ohms Law......no simpler versions available yet as far as I know....

Glad you like the all the long time Members like MrAl,alec-t,audioguru as well. I like them all too

When they speak, I listen very closely. So I can learn too.

My field is CRT TV. Know it well. Other than that , I listen and learn here. Love it .

Best Regards,
tvtech

haha can't I say dear to you?
I use 'Dear' to all nice people. They are respected peoples, some are very very aged like my grand pa and some are like my dad. Asian feel nice to say 'dear' to others

My dream to be an electronics engineer or to be a technician was broke very yrs ago. I cannot leave electronics so trying to fun with it.

 

[Willen]

.......ill be times when the efficiency is quite low meaning a large part of the energy stored in the battery goes to waste. This is the basic nature of the shunt regulator.

Is this design process more clear now?

sorry for asking again and again, but want to know another two things-

A) The schematics is designed for 10mA load current, what happens if I used 1mA or 0.1mA load here?

B) If i designed a shunt reg with 100mA Iout and if i connected a 3.6V NiCd 1.5Ah battery here as a load, then how can we express its load current? (Iload=?) anything bad?

 

[MrAl]

Hi again Willen,

First, as to the term of endearment, "dear", here in America we usually only say that to the opposite sex so you might get some bad results using it as you would in your country. It does not bother me anymore because i have heard this term used by other peoples in other countries on multiple occasions and i realize it is just a part of the culture. But as i said many people will find this strange here in this country so you may want to think about that. A good substitute here might be "dear friend".

So as for the circuit again, a lower load current also means more waste because the shunt regulator has to eat up all the extra power which is more now because less goes to the load. You can charge a battery with it too if the voltage is less than 5v but that's up to you...just make sure the battery is charging.

 

[alec_t]

Here's how a TL431 could be used as a voltage reference for a simple constant-current charger for a NiCd battery. There is very little power wastage in the '431; most wastage is in Q1. The values shown would give a charge current ~ 88mA, for supply voltages varying from 9V to 7V over a 15°C to 30°C temperature range. Note the WARNING! The circuit has no way of terminating the charge automatically so would be unsafe left unattended. I don't recommend building it: it's just for educational purposes to show the principle of operation.

 

[Willen]

Hi again Willen,

First, as to the term of endearment, "dear", here in America we usually only say that to the opposite sex so you might get some bad results using it as you would in your country. It does not bother me anymore because i have heard this term used by other peoples in other countries on multiple occasions and i realize it is just a part of the culture. But as i said many people will find this strange here in this country so you may want to think about that. A good substitute here might be "dear friend".

hahaha OH...now I knew why 'tvtech' laughed at me. I din't know that most part of the world has a meaning of dear is 'girlfriend' or 'boyfriend' .

This part of the world, we use normmally dear along with name, so I said 'dear tvtech'. (like 'dear sir' in official letters. )

Sorry tvtech, I knew that- you are not my dear hee hee hee.

Eventually I understand that shunt regulator works in very certain condition. Thanks lot.

Here's how a TL431 could be used as a voltage reference for a simple constant-current charger for a NiCd battery....

Oh yes! Another problem has been solved! But what is the charging voltage (Vout) here? Is it just a current limiter (instead of voltage reg.)?

Which simulation programme you used? I using LT spice but it has no TL431. (no good internet to update LTspice)

 

[alec_t]

But what is the charging voltage (Vout) here?

It's whatever the battery needs across its terminals to maintain the constant current, so Vout is variable. The circuit tries to hold the current constant; it doesn't just limit it to a maximum value.

Which simulation programme you used?

LTspice. You can download all sorts of models (including the TL431) free from the Yahoo LTspice User Group.

 

[alec_t]

Post deleted

 

[Willen]

It's whatever the battery needs across its terminals to maintain the constant current, so Vout is variable. The circuit tries to hold the current constant; it doesn't just limit it to a maximum value.
LTspice. You can download all sorts of models (including the TL431) free from the Yahoo LTspice User Group.

what will happen with 5V supply?

Um..... I am also in this group but I am using internet using cell phone (poor view), so I cannot get much more models there. Searched all in one pack in zip also cannot find. May be I need computer to use the group fully. Do you have some of them? If yes please attach here as a 'zip'.

 

[alec_t]

5V won't be enough for that charger circuit to charge a 3.6V battery.
Here's the '431 model and its symbol:

 

[Willen]

5V won't be enough for that charger circuit to charge a 3.6V battery.

Can't I use 5V supply even if I decrease the value of emitter resistor to around 5 ohms or less?

OK, now please choose a best simpler charger circuit from here for me:

https://www.eleccircuit.com/the-most-lead-acid-battery-charger-circuit-by-lm317/

I want to make simpler charging circuit for lead acid battery of around 12V, 10Ah so I need almost 1.5A charging current. I have LM317T so want to use it.

Or do you have any better than link? Please!

 

[alec_t]

Can't I use 5V supply even if I decrease the value of emitter resistor to around 5 ohms or less?

Not in my circuit. The emitter resistor is what sets the current. The 431 is configured as a 2.5V reference, so the emitter voltage is 2.5 - 0.7 = 1.8V. The collector voltage must be >1.8V, so the battery on charge would have to have a voltage < (5 - 1.8), i.e. < 3.2V.

I want to make simpler charging circuit for lead acid battery of around 12V, 10Ah so I need almost 1.5A charging current.

It won't be simple if it's to be safe, reliable and automatic and you want a long battery life. All of the circuits linked to have limitations.
Is your 12V battery a wet-plate type or SLA? What supply voltage will you use? What environmental temperature range will it be charged in? Will the battery be on permanent float charge or just charged periodically? Will it be unattended while charging? Which version of the LM317 do you have?

 

[Willen]

It won't be simple if it's to be safe, reliable and automatic and you want a long battery life. All of the circuits linked to have limitations.
Is your 12V battery a wet-plate type or SLA? What supply voltage will you use? What environmental temperature range will it be charged in? Will the battery be on permanent float charge or just charged periodically? Will it be unattended while charging? Which version of the LM317 do you have?

Not need MORE safe, but it would be better if battery charged fully then decrease charging current automatically. Also it would be better if there is LEDs for Full Charged Indicator (also battery low indicator if it is simple too).
I have both type of batteries listed by you. Room temp is normally 30 or more during summer (10/15 during winter). I have 'LM317T' (I think T version is higher power among 3). And I will use any supply volt as you prefer.

Do not think about VERY critical circuit, just I need a good for me . Few months ago I charged a 10Ah lead acid battery almost 15 hrs. Few days later I tested the charging voltage and it was 24V DC and 4A current hee hee hee

 

[alec_t]

Few days later I tested the charging voltage and it was 24V DC and 4A current hee hee hee

Well that will have shortened the battery life

 

[Willen]

Here's how a TL431 could be used as a voltage reference for a simple constant-current charger for a NiCd battery. There is very little power wastage in the '431; most wastage is in Q1. The values shown would give a charge current ~ 88mA, for supply voltages varying from 9V to 7V over a 15°C to 30°C temperature range. Note the WARNING! The circuit has no way of terminating the charge automatically so would be unsafe left unattended. I don't recommend building it: it's just for educational purposes to show the principle of operation.
View attachment 75069

I think Max.Power dissipation from 18 ohms resistor is (approx) 800mW. Then I have to use 1W (or 2W) resistor. Am I right?