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Topic: Is a 2n3906 an suitable substitute for a S8050? What about 2n3904 for a S3550? (Read 3227 times) previous topic - next topic

TECH GEEK

I'm mainly concerned about DC current gain although I don't fully understand what exactly gain is...
I expect the mA used by the circuit to be <70mA total. Probably 5mA to 20mA used by the transistors.

Datasheet for 2n39**
Datasheet for S8*50
As always... Thanks for posting!!!

Grumpy_Mike

We need to know what you are going to do with the transistor before we can say if this is a sutiable replacement.
Gain is the value used in:-
Base Current * Gain = Collector current

TECH GEEK

Quote
We need to know what you are going to do with the transistor before we can say if this is a sutiable replacement.

I'm not entirely sure actually...

I'm repairing a compass sensor module I found in a dumpster. When I first found the sensor my plan was to take the KMZ52 magnetic sensor IC off and
make it more compatible with my Arduino. Now I realize the module used I2C to communicate. Now I need to replace the burned-out capacitor and the 2 pairs of SN8**'s to make the module work as it used to.

To the best of what I know the 2 NPN's and 2 PNP's are used to turn on/off the KMZ52's 2 internal coils (the coils are in the SMD IC)
ohh one more thing Iooked at the KMZ52's datasheet and the pcb, I think the current that goes from collector to emitter is less than 4mA.
also it appears the NPNs and PNPs are in two half H-bridges...
As always... Thanks for posting!!!

Grumpy_Mike

Well they look very similar but the S8050 has a slightly higher gain. That shouldn't matter much in a H-bridge especially as such low loads.
Also the the S8050 gas a higher emitter base saturation voltage which is normally a bad thing but it might be in the design, it's impossible to tell.

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