replacement transistor for bs170

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menachg
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replacement transistor for bs170

Post by menachg » Sat May 02, 2015 9:51 pm

will a unisonic utc s8050/s8550 transistor work for the backlight control mod? it says its a low voltage high current small signal (pnp on the 8550 and npn on the 8050 i've got both) transistor i'm not so big on electronics so can anybody help me with that?


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MikeB
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Re: replacement transistor for bs170

Post by MikeB » Sat May 02, 2015 10:47 pm

Yes, the npn one looks fine.

Mike.
erskyTx/er9x developer
The difficult we do immediately,
The impossible takes a little longer!

menachg
Posts: 2
Joined: Sun Apr 26, 2015 4:11 pm
Country: Israel

Re: replacement transistor for bs170

Post by menachg » Sun May 03, 2015 7:43 am

what is the difference between the npn and the pnp and what are the crucial specs because i've seen some guys say on some different transistor that they could fry your control port by time so i'm a bite worried about doing this control mode so are you abselutley sure it would be fine to use the s8050 npn for the backlight control and it wont cause any problems in the future?

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MikeB
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Re: replacement transistor for bs170

Post by MikeB » Sun May 03, 2015 1:13 pm

The BS170 is a n-channel FET transistor. As such it is controlled by a voltage. You need to use a npn bipolar transistor (not pnp) to replace it, but as this is current controlled, you need a resistor (say 4.7K ohms) in series with the base connection.
It should then work without any problems.

Mike.
erskyTx/er9x developer
The difficult we do immediately,
The impossible takes a little longer!


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