if a transistor internally is causing fluctuating, what internally is wrong with the transistor? and what kind of state is the transistor in when it's fluctuating on the collectors output?
There is nothing wrong with it. I'm pretty sure that is what they are supposed to do. How about a schematic diagram. They are worth thousands of words or so I've been told by experts.if a transistor internally is causing fluctuating, what internally is wrong with the transistor? and what kind of state is the transistor in when it's fluctuating on the collectors output?
Yes very true, so what troubleshooting skills and techniques would u use or how would u approach this?Any node of a circuit has 2 or more components attached to it by definition. How would you know that an individual transistor is responsible if the voltage is fluctuating at a particular node? It could be a reaction of multiple components working in harmony together in response to some problem condition.
If a transistor is not a transistor and it just a parts has two diodes, then everything that you measuring is not equal to the transistor.I would first use a function generator and inject a .5 volts AC sine wave on the input of the base of the transistor and than see if the output is fluctuating.
That's True, But I have changed many transistors that was causes circuits to fluctuate or fluctuatingThere is no any fluctuating voltage will come from transistor when it is independent.
When a independent transistor didn't adding any voltages on it, then the transistor is not a logical circuit and it also is not a amplifier circuit, there is no hfe, there is no Ib, Ic, Ie, the transistor that it is only a parts including two diodes.
One test that's probably easiest is the base emitter voltage test. The base should be _about_ 0.7V above the emitter (in an NPN transistor). If the base is > 1V higher it's almost surely blown.Yes very true, so what troubleshooting skills and techniques would u use or how would u approach this?
Are you saying that you have a particular circuit that begins to behave strangely (it "fluctuates") and you already know which particular transistor is the problem and that you have changed it many times and then, after some time passes, the same circuit begins to behave strangely again?That's True, But I have changed many transistors that was causes circuits to fluctuate or fluctuating
The Transistor is the problem for sure, because when I change the transistor the circuit works , so it's the transistor for sure 100% only the transistor no other components around it cause the fluctuation
It the base to emitter voltage always 0.7 volts? when measuring it IN circuitis the base emitter voltage test. The base should be _about_ 0.7V above the emitter (in an NPN transistor). If the base is > 1V higher it's almost surely blown.
No, I'm saying if you are testing 100's of the same boards and each board has 50 transistors on it and one of them is fluctuating but you don't know which one out of the 50 is doing it , how about you find it and when troubleshooting skills and techniques would you do to track the bad transistor?Are you saying that you have a particular circuit that begins to behave strangely (it "fluctuates") and you already know which particular transistor is the problem and that you have changed it many times and then, after some time passes, the same circuit begins to behave strangely again?
Yes, you do this in-circuit while it's powered on and put one probe to the emitter and one to the base in DC mode.It the base to emitter voltage always 0.7 volts? when measuring it IN circuit
Because when I measure the base and emitter I get DC offset voltages not 0.7 volts
How do you do the emitter to base test to get 0.7 volts? did you switch your DVM meter to diode mode or you using DC volt mode?
No idea on that.No, I'm saying if you are testing 100's of the same boards and each board has 50 transistors on it and one of them is fluctuating but you don't know which one out of the 50 is doing it , how about you find it and when troubleshooting skills and techniques would you do to track the bad transistor?
Would you start by doing what?
by Jake Hertz
by Jake Hertz
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