Peak Atlas DCA75 Pro User Manual page 19

Peak Atlas DCA Pro User Guide June 2019 – Rev 1.7
Free Wheeling Diode
Some transistors, particularly CRT deflection transistors and
many large Darlingtons have a protection diode ("free
wheeling diode" or "body diode") inside their package
connected between the collector and emitter.
If a free-wheeling diode has been detected, it is shown on the
schematic symbol. Some examples are shown here:
The Philips BU505DF is a typical example of a diode protected bipolar
transistor. Remember that the diode (if present) is always internally connected
between the collector and the emitter so that it is normally reverse biased.
For NPN transistors, the anode of the diode is connected to the emitter of the
transistor. For PNP transistors, the anode of the diode is connected to the
collector of the transistor.
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