I have some questions about interpreting the information found of a standards 2N222. I have received tons of help from some good people and understand the principle of how BJTs work.
The problem I am trying to solve is why a transistor seems to get hot when it its actuating an electromagnet rates at 1A IF such electromagnet stays on for more than 2-4 seconds.
Needless to say I have been doing much reading and watching videos in efforts to better understand what I am looking at when looking at the datasheet of a standard PNP 2N222 and I have some questions.
Let me start by saying that I bought this transistor at radio shack and I cannot find a data sheet for a 2N222. therefore I am using this as starting point or point of reference.
I know that there needs to be a current between the Base and Emitter to turn on the transistor (Hfe).
I also know that there is a current multiplier of across the collector and Emitter.
By questions are:
I am but confused with some information found the data sheet. (please correct me where I am wrong)
First under Absolute Max Rating. There is Vebo with a max of 6.0 v. This tells me that the base should not be supplied with a voltage near or exceeding 5v. A High from an arduino through a resistor should be okay.
Now, when I look at the ON Characteristics, is shows:
a min. of 0.6v and a ax of 1.2V in one instance and a max 2V with no min on the other. I find this confusing.
Does this take into account the 0.7v or in this case the 0.5v capacitance value?
Last, how does one properly interpret the Current Gain conditions to achieve the multiplier on the chart?
In essence I would like to to be able to identify how much current it takes to turn on a transistor, and how much voltage it needs to work. additionally I would like to know how much current can flow though it before it gets hot and breaks. All in efforts to asses and understand the cause of my problem.
Here is my circuit.
based on this, 12v-0.6v / 1000 = I 11.4 mA. from base to emitter… that is all I know…