TIP120 transistor base current from arduino

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hello!

im using tip 120 transistor drive solenoid 12v , 1.5a

cant work when use analog pin directly base close transistor?

 the thing works if have smaler transistor helps tip 120 "close".

 do need 2 transistors drive solenoid? have tested use flyback diode , without resistor , doesnt work either when have tip120.

the smal transistor s8050


this wiring works


photo host

this wiring doesnt work


how print screen

quote
cant work when use analog pin directly base close transistor?
well should, must doing wrong. have set pin output in setup function?

i surprised circuit works works. there no pull resistor on smaller transistor there no source current base. again must doing other show in first diagram.


quote
do need 2 transistors drive solenoid?
no.

quote
i have tested use flyback diode
put need it.

quote
and without resistor
put or damage arduino.


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