2N3055

[3][4][5] The exact performance characteristics depend on the manufacturer and date; before the move to the epitaxial base version in the mid-1970s the fT could be as low as 0.8 MHz, for example.

The total power dissipation (written PD in most American datasheets, Ptot in European ones) depends on the heatsink to which the 2N3055 is connected.

Modern 2N3055 datasheets often, but not always, specify fT of 2.5 MHz (minimum) because some improvements have been made over time (especially the move to the epitaxial manufacturing process).

Nevertheless, a 2N3055 (and many other power transistors originating from this era) cannot be assumed to have great high-frequency performance and there can be degradation of phase-shift and open-loop gain even within the audio frequency range.

The historically-significant 2N3055 was designed by Herb Meisel's engineering group with RCA; it was the first multi-amp silicon power transistor to sell for less than one dollar, and became an industry workhorse standard.

The team of design, production, and applications engineers received RCA Electronic Components achievement awards in 1965.

[1] Several versions of the 2N3055 remain in production; it is used in audio power amplifiers delivering up to 40 W into an 8 ohm load[12] in a push–pull output configuration.

In the sixties and early seventies, Philips produced similar devices encapsulated in TO-3 packages under the reference BDY20 (described as being for "hifi" purposes) and BDY38 (although the BDY38 has lower voltage ratings than the 2N3055).

[14] They were used extensively in the former Eastern Bloc countries in audio power amplifiers made by Czechoslovakian Tesla, Polish Unitra.