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Topic: Transistor as as switch - replace BC547 with S8050 (Read 319 times) previous topic - next topic

botzko

Hello,

When transistor is used as a switch what parameters I should look to find suitable replacement?
I need to find out is S8050 suitable replacement for BC547.

Kind regards.

bigred1212


https://www.sparkfun.com/datasheets/Components/BC546.pdf

Collector-Base Voltage
BC547/550       50

Collector-Emitter Voltage
BC547/550       45

Emitter-Base Voltage
BC546/547       5

Collector Current (DC)
100  mA

Collector Power Dissipation
500  mW

DC Current Gain
VCE=5V, IC=2mA     110-800


http://media.nkcelectronics.com/datasheet/s8050.pdf

Collector-Base Voltage V
30
                                   
Collector-Emitter Voltage
20
                                   
Emitter-Base Voltage
5

Collector Dissipation(Ta=25°)
1  W
                                                                           
Collector Current
Ic 700 mA

DC Current Gain(note)
hFE     110-400



The BC547 is categorized as "designed for use as general purpose amplifiers and switches requiring collector currents to 300 mA."

The S8050 is categorized as "a low voltage high current small signal NPN transistor, designed for Class B push-pull audio amplifier and general purpose applications." 

Mikeb1970

Hello,

I looked at the datasheets of both transistors, and almost right away I noticed the "large" difference of the max voltages. Since I don't know in what kind of circuitry you want to use the S8050, more particularly what the max voltages are, I can't determine if you can use S8050. Are you from Europe? The BC547 was a very popular transistor used in European magazines, especially in Belgium and the Netherlands.

Here are some images taken from the datasheets.


I hope this helps you.

Mike

Darn, I can't post the images in the text, had to include them as attachments, sorry
   

MarkT

Hello,

When transistor is used as a switch what parameters I should look to find suitable replacement?
I need to find out is S8050 suitable replacement for BC547.

Kind regards.
For a switch the saturation characteristics (including turn off time), leakage current, and max voltage are the main parameters you care about.
[ I will NOT respond to personal messages, I WILL delete them, use the forum please ]

botzko

Thank you all.

@Mikeb1970 the voltage is 12V, so this should be fine because both transistor support higher voltage.

@MarkT - may be stupid question but what are the saturation characteristics for the transistor? Also I'm checking
https://www.sparkfun.com/datasheets/Components/BC546.pdf and
http://media.nkcelectronics.com/datasheet/s8050.pdf
but can not find the turn off time.

Mikeb1970

At 12 volt there are no problems indeed on this part.
I'm sure I have a BC547 here, the biggest problem is were is it located.
Anyway, would it help you out if I could send it to you?

botzko

Thank you @Mikeb1970. I will be able to buy BC547 but I will use the S8050 because I have it :).

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