hello i see the 2n3553 NPN power transistor for rf.
i see these statements

Minimum Gain: 10dB
Efficiency: 50%

what is "Gain: 10dB" meaning?
why they show us the effeciency of transistor?it doesn't related to circuit that we design? for example class A or class C?

Thanks

Why you didn't ask any of following and other manufactirers directly? All manufacturers have frindly tech support team.

2N3553 Advanced Semiconductor, Inc.
2N3553 Advani-Oerlikon Ltd.
2N3553 Continental Device India Limited
2N3553 Ferranti Semiconductors
2N3553 ITT Semiconductors Semiconductor
2N3553 Motorola
2N3553 Mullard
2N3553 Philips Semiconductors / NXP Semiconductors
2N3553 RCA Solid State
2N3553 Semelab NPN Silicon
2N3553 Semicoa Semiconductor
2N3553 Semitronics Corp.
2N3553 Solidev Semiconductors
2N3553 STMicroelectronics
2N3553 SunLED Company Limited
2N3553 Texas Instruments
2N3553 Transistor International Corporation

Above an old data of it manufacturers, I hope currently more companies produce it.

Thanks i don't think about it.i ask if they don't answer me i ask gain in this forume

Gain in dB = 10*log(Pout/Pin)

they show typical params for typical application (see fig. 6 on page 5):
http://html.alldatasheet.com/html-pdf/1507...5/5/2N3553.html