need ur help

[Emantra]

Hello there,

I'm a little problem here. First I wanted to use a TIP 110 NPN and NTE 262 PNP darlington amplifier, which I had to change coz I couldn't find that in the market I also searched for the replacement also which I was also unable to find. So I'm designing a darlington amplifier for both the transister.

Both are TO220 Darlington transistor
NTE262: PNP, 100V, 4A, 65W, hfe=2500 at 4A
TIP110: NPN, 60V, 2A, 50W, hfe>1000

Could u guys just see my schematic n tell me what can I add n remove? And any comment .

thanks for any reply

 

[bloki]

You can use BDX33A for TIP110 and BDX34A for NTE262.
In your first schematics diode must be reversed, just oposite as in second one.
First resistor can be 10kohm and second is better to be smaller. It can be 220-560ohm.

 

[Joel Rainville]

You can use BDX33A for TIP110 and BDX34A for NTE262.
In your first schematics diode must be reversed, just oposite as in second one.
First resistor can be 10kohm and second is better to be smaller. It can be 220-560ohm.

Guys,

I don't know much about transistors, I'm just playing with that first schematic in my simulation software. A first resistor of 10k with a smaller second one gives out a nice strong current at the collector with just a couple mA at the base.

But wouldn't reversing the diode just short the whole thing?

 

[bloki]

Diode in first circuit now shorts second transistor. It must be reversed.
And I think transistors 2N2222 are used in circuits only symbolically. This transistor is NPN and can not be used in second circuit. Also this transistor has not current and power ratings to replace the second transistor. For this transistors BD241 and BD242 can be used respectively.

 

[Joel Rainville]

Woops, right. I had the emitter and collector reversed. It's even more powerful with the diode reversed and the polarity right :lol:

The second resistor has a huge influence on the total output. [Edit : Wrong. This was only true on my first try with the E & C reversed.]

 

[Emantra]

Thanks for your help

First of all I'll try to find the BDX33A and BDX34A in the market, if I couldnt find them also I'll follow what u have said.

The diode in the first schematic is the revesred one, I forget to change its polarity coz it is the copy of the second schematic which I drew first, I changed only the transistor but forget to change the polarity of the diodes.
Sorry for that.

Thanks a lot.

 

[Emantra]

Hey there,


I searched the market I couldn't find the BDX33A instead of that I am using BDX33C which I found out that both are some what similar but the only thing that differ is the voltage it works 33A has 60V whereas the 33C has 100V, so does this difference in the voltage create problem? and I cpouldn find the BDX34A so I think that I had to design the Darlington amplifer myself.

Is my desing right?? If no what are the changes that I had to make here.

Thanks for any comment

 

[bloki]

Types A, B and C differs only by voltage reting. The higher it is the better. Have you searched for BDX34 types A, B or C.

You can use TIP132/TIP137, TIP120/TIP125, TIP121/TIP126 or TIP122/TIP127 pairs.

 

[Emantra]

I did search, I couldn find the BDX34's any type.

So I am opting for desige this amplifier. And are these replacement pairs for the BDX34 or they are for something else.

 

[bloki]

These transistors are practically equivalents for BDX33/BDX34 pair.

 

[Emantra]

I'll again give a try.

But can you give me replacement in other then in the TIP's coz these are little difficult to find in my place.

Thanks for help.

 

[bloki]

Next simillar types are BDX53/BDX54, BD901/BD902 or BD649/BD650.

 

[Emantra]

hello,


I belive these replacement are for TIP110/NTE262,

Is BD241/BD242 are also the replacement for these, or for the darlington amplifer design.

 

[bloki]

These BD241/242 are for Darlington design. They are single transistors.

 

[Emantra]

Ok, I got the transistor BDX33C/BD650.

So will thesetransister replace the TIP110/NTE262 won't there be any problem???

 

[bloki]

I do not expect any problems.

 

[Emantra]

Thanks a lot for your help.

I'll contact you if I got into any problem.


Thanks.

 

[Gorgon]

Hi,

You can also use the following darlington pairs:

BD677A (NPN) & BD678A (PNP) 60V, 4A, hfe 750, TO126

BD679 (NPN) & BD680 (PNP) 80V, 4A, hfe 750, TO126

Both are complementary pairs.


TOK