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AF125 Transistor Data

Key transistor data for the AF125 germanium PNP high frequency (for its day) transistor including key electrical parameters, pinout, package type and many other key transistor details.

The AF125 is a PNP germanium diffusion alloy transistor intended for use as an FM pre-stage amplifier, but it was often used in many RF circuits.



Key details and performance parameters for the AF125 transistor.


Transistor parameters & data
 
Parameters Details
Transistor type PNP germanium transistor
Package type TO72
VCBO max (V) 32
VCEO max (V) 15
VEBOmax (V) 2
IC max (mA) 10
TJ Max °C 75
PTOT mW 75
fT min (MHz) 75
COB 3p
hfe 50 min
IC for hfe 1 mA
Similar / equivalents 2N990

    Outline:



    Pinout:

Notes:   The AF125 was a later transistor than the AF117 series and is often used as a replacement for that series if one can be obtained. The specificatiosn and parameters for the AF125 are very similar to the AF124.



Explanation of transistor parameters


Parameter Explanation
VCBO Max Maximum collector-base voltage with emitter open circuit .
VCEO Max Maximum collector-emitter voltage with base open circuit.
VEBO Max Maximum emitter-base voltage with collector open circuit.
VCEsat (included where applicable) The voltage drop across the collector-emitter when the transistor is fully saturated (acting as a closed switch).
IC Max Maximum collector current.

Parameter Explanation
TJ Maximum junction temperature.
PTOT Max Maximum device dissipation normally in free air at 25°C unless other conditions indicated.
fT Min Minimum cutoff frequency at which the current gain in a common emitter circuit falls to unity.
COB Max Maximum collector capacitane, normally measured with emitter open circuit.
hFE DC current gain for HFE at IC. [Note hfe is the small signal gain and although this may be slightly different, the transistor current gain will vary considerably from ne transistor to the next of the same type.]
PTOT Max Maximum device dissipation normally in free air at 25°C unless other conditions indicated.

These are the main transistor parameters that have been included in our list. There are others, but these help quantify the main elements of the performance of the transistor.

 



Please note, that the data given is the best estimate we can give within a tabulated summary of this nature. Parameters also vary between manufacturers. Electronics Notes cannot accept any responsibility for errors, inaccuracies, etc, although we do endevaour to ensure the data is as accurate as possible.

Ian Poole   Written by Ian Poole .
  Experienced electronics engineer and author.




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