Update: A diode in this position is (at least sometimes) referred to as an anti-parallel diode. This term brings up a lot more results on search.
I've been scavenging parts from compact fluorescent (CFL) bulb ballasts just for the sheer joy of getting something for free. Plus, I'm all into inductors just now and there are some nice little specimens in there yearning to be rewound and repurposed :)
One of the parts I'm finding is a 200V NPN power transistor in a TO-220 package, the 3DD4126PL (marked D4126PL). There's a datasheet for it here if anyone is interested.
The schematic symbol for it in the datasheet includes a reverse diode symbol, like a MOSFET does:
Unless it's escaped me for quite a while now, an NPN BJT doesn't naturally have a built-in body diode the way a MOSFET does, does it?
Can anyone explain what this added bit in the symbol means? Is a bypass diode added as an extra in this case, perhaps because it's meant for high-ish voltage operation in a fluorescent ballast (albeit a pint-sized one)?