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2SC1971 Vs 2SC1972

Imalu3055

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Hi!
The 2SC1971 output transistor of my FM transmitter burned out and since I don't have a similar one I replaced it with a 2SC1972. I observed the characteristics of both and except for the power dissipated, everything is the same. I solder it on the board when I energize it, there is a quiescent current of 4 Amp and there is no RF at its output. I think it must be a polarization problem. What I do not understand, they are identical! Has anyone had a similar experience?

Thank you
 

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Imalu3055

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In electronics parts stores it is common. The only problem is that apart from the original Mitsubishi there are "TRUCHOS" (false) and they do not behave in the same way.
 

BigBoss

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In electronics parts stores it is common. The only problem is that apart from the original Mitsubishi there are "TRUCHOS" (false) and they do not behave in the same way.
That's why I asked where did you buy it ..Because I know there are many counterfeits for obsolete components.
This transistor has been obsolete years ago and therefore I recommend you to modify your design/circuit for a newer part.
 

vfone

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At 4A quiescent current, your "truchos" is dead..
When buy from the net this kind of osolete RF power transistors, bigger chances to get a good one is to buy used (second-hand).
Then, you will stay only at the mercy of probability to get a bad one, when if they are new the chances to get a bad one are almost 100%.
 

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