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AC128 Transistor Data
Key transistor data for the AC128 germanium PNP audio transistor including key electrical parameters, pinout, package type and many other key transistor details.
The AC128 was a popular PNP germanium low frequency or audio amplifier transistor that was used in many circuits in the 1960s and early 1970s.
Key details and performance parameters for the AC128 transistor.
| Transistor parameters & data |
|
|---|---|
| Parameters | Details |
| Transistor type | PNP germanium transistor |
| Package type | TO1 |
| VCBO max (V) | -32 |
| VCEO max (V) | -16 |
| VEBOmax (V) | -10 |
| IC max (mA) | -1000 |
| TJ Max °C | 100 |
| PTOT mW | 260 |
| fT min (MHz) | 1 |
| COB | 200p |
| hfe | 45 - 165 |
| IC for hfe | -500 mA |
| Similar / equivalents | 2N2706 |
Outline:
Pinout:
Notes: This transistor was a widely used in its day in a variety of different relatively low power and low frequency (audio) applications.
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 parameers 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.
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