Sensing ambient light

[premkumar9]

I got that one and get millions of other datasheets from Datasheet Archive - Free Datasheet Search Engine :: PDF Datasheets :: Data Sheet :: Datasheet :: Application Note : çš„å￾‚æ•° : 规æ*¼ä¹¦ : 技术资料 : ë￾°ì￾´í„°ì‹œíŠ¸ : データ・シート : Fiche technique : Datenblatt : опиÑ￾ание .
They have a limit of about 25 per day but my router gives them a different address each time so I have no limit.

THANK YOU FOR THE INFORMATION

 

[premkumar9]

Simply look on the datasheet for the AT89C2051 micro-controller to see that its max allowed voltage on any pin is +7.0V and that your R9 is connected to +12V which might destroy it.

R9 should be connected to the +5V supply of the micro-controller.

Since you cannot get a logic-level Mosfet then test many of the ordinary Mosfets to find one that works with an input of 5V.

What about this? Can you suggest any better solution to connect IRFZ44N with 89C2051?

 

[blueroomelectronics]

What about this? Can you suggest any better solution to connect IRFZ44N with 89C2051?

A MIC4427 includes a pair of MOSFET drivers. Nice part and not too hard to find as lots of manufacturers make it.

 

[kchriste]

What about this?

No, that won't work because the Vbe drop of the BC177 will not allow it's emitter to go below 0.7V which will cause the BC107 to remain on no matter what.

Can you suggest any better solution to connect IRFZ44N with 89C2051?

BlueRoom's idea is good. If you can't find that exact chip, Google for "low side mosfet driver" for different ones.

 

[audioguru]

Does anybody still make a very old BC107 and BC177 transistor? I used them at the beginning of my electronics career in about 1963 (45 years ago).
Does anybody remember the old metal cases on the very old transistors? I still have some.

Why are we talking about ancient history?

 

[premkumar9]

No, that won't work because the Vbe drop of the BC177 will not allow it's emitter to go below 0.7V which will cause the BC107 to remain on no matter what.

The transistor BC177 will be in saturation and and hence its collector voltage will not be enough to ON the BC107. Am I right? Anyway that is not safe. What about this change (refer attachment)?

 

[premkumar9]

Does anybody still make a very old BC107 and BC177 transistor? I used them at the beginning of my electronics career in about 1963 (45 years ago).
Does anybody remember the old metal cases on the very old transistors? I still have some.

Why are we talking about ancient history?

Many equivalents are available. You are a very senior person. Sorry if any of my words was hurting to you.

 

[kchriste]

The transistor BC177 will be in saturation and and hence its collector voltage will not be enough to ON the BC107. Am I right?

No, because the base voltage of the BC177 cannot be lower than it's collector. If it was in true saturation, the base voltage of the BC177 would have to be apx 0.6V lower than it's collector.

Anyway that is not safe. What about this change (refer attachment)?

Yes, that would work.

Many equivalents are available. You are a very senior person. Sorry if any of my words was hurting to you.

The BC177 and BC107 make AudioGuru feel old and that makes him grumpy.

 

[premkumar9]

No, because the base voltage of the BC177 cannot be lower than it's collector. If it was in true saturation, the base voltage of the BC177 would have to be apx 0.6V lower than it's collector.

True. So BC177 will never go to saturation in this circuit?

 

[Mikebits]

My special team of reporters has been able to uncover the true identity of AG. One of our crack team reporters captured this exclusive photo.

**broken link removed**

Just kidding AG...

 

[kchriste]

True. So BC177 will never go to saturation in this circuit?

Exactly! You are operating the BC177 as a buffer / common collector amplifier.

 

[transistor495]

The BC177 and BC107 make AudioGuru feel old and that makes him grumpy.

Ni-Cad battery also .
Now guruji uses energy packed 2500mAh NiMH energizer batteries.......

 

[premkumar9]

My special team of reporters has been able to uncover the true identity of AG. One of our crack team reporters captured this exclusive photo.

**broken link removed**

Just kidding AG...

Probably this picture was taken just after AG saw a post from a third world country.
Again Joking only.

 

[transistor495]

In the golden ages AG was a smart handsome guy that I can catch up from the face. I'm not joking............yea never mind

 

[audioguru]

My wife and I think I still look handsome.
Some of the pretty young nurses at the eyes surgery place were flirting with me and I flirted back.
Guess what! A few of the pretty young flirting nurses are from India.

The very old transistors remind me of my first job which was at Philips.

You don't need a zener diode. An ordinary forward-biased diode will work fine like this:

 

[premkumar9]

My wife and I think I still look handsome.
Some of the pretty young nurses at the eyes surgery place were flirting with me and I flirted back.
Guess what! A few of the pretty young flirting nurses are from India.

:

I doubt whether it was a eye hospital. Must be a mental hospital. Your memory might have faded now

 

[audioguru]

I doubt whether it was a eye hospital. Must be a mental hospital. Your memory might have faded now

I recently had cataracts surgery to both eyes that suddenly got cloudy lenses. Now I can stare at the pretty young women and see them extremely clearly.