# Output current in collector of BC107

I am working on following circuit involving BC107 NPN Philips TO-92 transistor and voltage source of 4.2 V.

simulate this circuit – Schematic created using CircuitLab

I got some confusion when measuring collector's current. I was expecting that to be at least 0.2 A but when I insert probes and measure current as shown in the picture I get a reading of 0.0079 A. That would mean an DC Gain (beta/hFE) of Ic/Ib=0.0079/0.0023=~3.37, while this transistor should yield a gain of about 40-200 (I do not have spec for TO-92 though, it's taken from datasheet for BC107 TO-18, can't find any spec for TO-92...).

I would like to understand why am I getting 0.0079 reading when the base current (Ib) is 0.00234 A (confirmed with multimeter).

Ib = (4.2 - 0.7) / 1480 = 0.0023

Ic (expected) = Ib * hFE = 0.0023 * [40:200] = [0.092:0.460] [A]

but real Ic = 0.0079 [A]

• Comments are not for extended discussion; this conversation has been moved to chat. Any conclusions reached should be edited back into the question and/or any answer(s). Dec 23, 2018 at 17:29