Transistor tester circuit

This is a simple project.it will test all types of transistors.Whether your transistor is Darlington and power. The circuit that has been shown here in the picture is set to test NPN types transistor. If you have PNP types of transistor then, connect the 9v battery around the other way at points A and B as shown in the picture diagram.
The transformer that has been shown in the photo is a 10mH choke with 150 turns of 0.01mm wire wound over the 10mH winding. The two original pins (with the red and black leads) go to the primary winding and the fine wires are called the Secondary winding.
Connect the transformer either way in the circuit and if it does not work, reverse either the primary or secondary (but not both).It will make one terminal High voltage and other terminal Low voltage.
Almost any transformer will work and any speaker will be suitable for the circuit.But try to you as it has been told here.
If you use the speaker transformer described in the Home Made Speaker Transformer article, use one-side of the primary.
if you have any type of problem regarding this circuit then tell me.