This is one of the transistor types.
Part Number : C1971, 2SC1971
Function : Silicon NPN epitaxial planar type transistor
Package : TO-220 Pin type
Manufactures : Mitsubishi
C1971 is a silicon NPN epitaxial planar type transistor designed for RF power amplifer on VHF band mobile radio applications.
4 to 5 watts output power amplifiers in VHF band applications
1. High power gain : Gpe >= 10dB
2. Emitter ballasted contruction, gold metallization for high reliability and good performances
3. Ability of withstanding more than 20:1 load VSWR when operated at Vcc = 15.2V, Po=6W, f = 175Mhz