Discussion in 'General Electronics Chat' started by joni, Nov 4, 2009.
The collector is connected to the case of the part.
Here is a data sheet for the part from ONsemi. If you look on the very last page, in small print under the table, it shows the connections.
pin 1 base
pin 2 emitter
It certainly doesn't jump out at you...
I looked again at the data sheet in the link you provided and the pinout is on the front page, inside the box with the part dimensions. It did not immediately jump out to me at first, which is why I looked at ONsemi.
Here is a link to the AllAboutCircuits book about transistors.
The specific transistor(s) that you have picked works like any NPN or PNP transistor, depending on which one from the data sheet you intend to use. You have the two pins for the base and emitter. For the collector, you need to electrically connect the case of the part to the circuit. All three connections are present.
Does that answer your question or do you have something more specific in mind?
The collector is connected to the housing.
The entire outer shell of the device is connected to the collector of the transistor.
The mounting hardware, screw and nut and washers can be used to connect a wire from the outer casing to the rest of the circuitry. The two holes in the wings are for the mounting hardware.
Or, if you are making a PCB, the part decal should have a pad that allows for the physical connection of the shell to the wiring on the board. Some conductive paste may be necessary as well...
There are sockets for TO-3 devices available (the 2N3055 is in a TO-3 package). They make connections easier, but you will need to use an insulating pad to keep the collector from shorting to the mounting surface.
2N3055's are famous for inefficiency, so they get hot. They almost have to be mounted on heat sinks.