I have a bunch of Darlington NPN Transistors TIP142 that are removed from two separate identical boards. The 1st one have the TO−218 CASE (left side of the image) and the 2nd the TO−247 CASE (right side of the image)
With the Diode Test when I measure the Base-Emiter with N-Probe to Base and P-Probe to Emmiter with the TO−247 I get about 1.368V for all of them, but the same measurement for the TO−218 is OL for all of them (Please note that the multimeter with no probes connected is also indicate OL).
The resistance between them is for the TO−247 about 3.56KOhm and for the TO−218 about 15KOhm.
The other measurements seems to be identical.
So I am really confused and I wonder if some of them are faulty.
Edit: In my opinion since there are two resistors in series between Base and Emitter there should be a voltage drop. In the TO-247 case my multimeters show OL maybe because there is no much current to draw to show any measurements. Note that the resistance in that case is about ~15KOhm instead of the 3.56Kohm of the TO-247. The datasheet referes that the 1st resistor is ~8K but for the 2nd just ~40 ???? what ?