Given how important transistors are to electric circuits, it is unfortunate that they are easily damaged due to mishandling either by,

• placing the wrong value resistor into a circuit.
• placing the transistor into the circuit backwards
• heating the transistor for too long with a solder pen.

To further complicate the issue, it isn't easy to determine whether a transistor is blown without the support of a DMM. Fortunately, there is a simple method to determine if your transistor is working properly.

1. Set your DMM to "Diode" (Internal diodes form an important component within a transistor and we're going to determine whether they remain viable)
2. Take the transistor out of the circuit and place it (isolated) into the breadboard. The 3 legs should not touch.
3. Connect the probes as shown below and confirm the suggested results for a working transistor.

Your transistor is BLOWN if,

• an OL reading comes back when you should get a reading. (the internal diode is burnt out)
• a Reading comes back when it should be OL. (the internal diode is shorted)
• a Reading is completely out of range. (below .6 or above .8)