Circuit design - urgently

[Annie]

Hi everyone,
I am not very good in electrical engineering and I am having a project which is i don't know where to start and how to build it. Can u please give me a hand and explain me briefly what exactly do I have to do, I am very appreciate

This is the topic----->>>>
Constant current NiCad battery charger: NiCad batteries are relatively simple to charge; for
standard slow charging they merely require a constant current at C/10 (10% of the rated
capacity) for 14 - 16 hours, most NiCad batteries also support fast charging whereby a constant
current source at C/5 is applied for 7 - 8 hours. Ideally such chargers should also include some
form of electronic control that monitors temperature and cell voltage to prevent overcharging
and/or overheating. For this project, though, you only need to design a single BJT transistor
based constant current source capable of supplying a fixed current of ~100 mA to a low
impedance load, independent of supply voltage and load impedance variations (within
reasonable limits).

 

[dougy83]

Have a look at https://www.google.com.au/search?sourceid=chrome&ie=UTF-8&q=current+mirror
**broken link removed**

 

[Annie]

oh thanks for that but what specific topic do I really have to look at?

 

[Boncuk]

You might want to take a look at the MAX712/MAX713 datasheet.

They can charge any number of cells from one to 16 cells either NiCad or NIMH batteries.

Boncuk

 

[Annie]

I found it's better now but do u have any thing else in more details which is related with the topic? I still can't figure out how to actual build the circuit as the topic require.....
thanks for ur help ;D

 

[ericgibbs]

I found it's better now but do u have any thing else in more details which is related with the topic? I still can't figure out how to actual build the circuit as the topic require.....
thanks for ur help ;D

Hi,
This is about the simplest using a single BJT.

 

[audioguru]

oh thanks for that but what specific topic do I really have to look at?

The Sound.Westhost article shows Real Life current sources.
Here is one.

 

[Annie]

can u please write me some easiest understanding explain as I'm a beginner

 

[audioguru]

can u please write me some easiest understanding explain as I'm a beginner

The extremely simple circuit has only 5 parts. If you don't understand it then you must learn about the basics of electronics, or ask your teacher.