2017-08-19 Emitter Base Breakdown Can Damage Transistor 

From YT reply to Neilgn  2017-08-20

Take any NPN transistor and measure the gain, and write it down.  Then put a 1k resistor in series with the transistor’s emitter and connect the emitter to positive and base to negative of a power supply.  Adjust the voltage until 2 or 3 volts are across the 1k resistor.  The voltage across the E-B junction should be more than 5 volts, maybe 7 or 8 V.  Now remove the transistor and measure the gain again.  When I did this years ago, the gain went from over 200 to less than 150.  I don’t know what causes this, but I’ve never seen any transistor that doesn’t do it.  When I did this, I cut off the leads of the transistor afterwards, because I was concerned about the damage to the transistor. 

The JT is only about 50 to 60 percent efficient, so if you have just a single current limiting resistor, it and the LED could be more efficient than the JT.

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