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replacement transistor for bs170
Posted: Sat May 02, 2015 9:51 pm
by menachg
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?
Re: replacement transistor for bs170
Posted: Sat May 02, 2015 10:47 pm
by MikeB
Yes, the npn one looks fine.
Mike.
Re: replacement transistor for bs170
Posted: Sun May 03, 2015 7:43 am
by menachg
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?
Re: replacement transistor for bs170
Posted: Sun May 03, 2015 1:13 pm
by MikeB
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.