Home » Component data » Transistor data » this page
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.
Written by Ian Poole .
Experienced electronics engineer and author.
Return to Component Data menu . . .
