9014 Direct Replacement???

[bigkim100]

Ok, simple question, I have a 9v circuit that flashes a led. The output of the LM358 is a 9014 transistor. I want to add more LEDs but the 9014 gets a little warm....is there a power transistor that can directly replace it????

 

[Martaine2005]

You could try a 2N2222 NPN.
It should give a few more mA.
Failing that, an N channel mosfet or a relay.
Show us the circuit and somebody will be able to give you a more precise answer.
Depending on the LED wiring configuration, you may be able to run more on your existing circuit.

Martin

 

[bigkim100]

Here it is, its not very exacting as far as components go

 

[bertus]

Here it is, its not very exacting as far as components go

Hello,

The schematic is VERY small.
I can not read any values.

Bertus

 

[Audioguru]

Here it is, its not very exacting as far as components go

Your schematic is too small to see its details, but it looks like the dual opamp is a triangle wave generator driving the transistor as a linear emitter-follower. Then of course the little transistor gets hot and so will any little transistor. Add a power transistor to drive your bunch of "breathing" LEDs and the little transistor can drive the power transistor. With many LEDs then the power transistor will need a heatsink.

 

[Bluejets]

Use a decent mosfet and you can add the LEDs till the cows come home.

 

[Audioguru]

The transistor here is used as an emitter-follower. If an N-channel Mosfet is used then its gate must have a fairly high voltage for it to be a source-follower.

 

[Bluejets]

It has me beat why they insist on switching on the high side.

So simple to use an n-channel mosfet ( logic level if required) and take the LEDs to ground.

 

[Martaine2005]

I think this circuit slowly dims and brightens the LEDs rather than just switching on and off.

Martin

 

[Audioguru]

The dual opamp creates a triangle waveform that slowly brightens the LEDs then it slowly dims the LEDs. The transistor is an emitter-follower that is linear (not a switch) so it gets hot.

 

[bigkim100]

Do I drive the NChannel Mosfet from the existing transistor, or directly from the IC

 

[bigkim100]

Hello,

The schematic is VERY small.
I can not read any values.

Bertus

It is listed in google under"Breathing LED"

 

[Martaine2005]

If you see it listed, why ask?.

 

[bigkim100]

If you see it listed, why ask?.

Dont get what you are saying, nobody has pecifically said what is driving it

 

[bertus]

Hello,

Wich circuit on google?
There are MANY:
https://www.google.com/search?as_st...&as_sitesearch=&safe=images&as_filetype=&tbs=
We can not help you without the used circuit.

Bertus

 

[Audioguru]

Here is the tiny schematic posted and a larger one from Google. The transistor cannot be a Mosfet unless you use a much higher supply voltage and change some resistor values. Use a power Sziklai follower.

 

[Martaine2005]

I had to Google that, thank you.
For anybody else interested here.

@Audioguru can you please explain how that works?.
The darlington is the same pair and this is a complimentary pair. Q1 collector is connected to Q2 base, that confused my little brain.

Martin

 

[Audioguru]

As a follower, the Sziklai pair has half the voltage loss of a darlington but it has the same current gain.

 

[Martaine2005]

Ok, I still don’t understand.
With the collectir of Q1 to base of Q2, sorry I can’t get my head around that configuration.
Perhaps you could explain in layman terms please.

Martin

 

[Audioguru]

The collector of the NPN turns on the base of the PNP. The PNP is a power transistor on a heatsink so it can have a high output current.