First, the role of an FET, the FET can be used as a variable resistor. 2, the FET can be conveniently used as a constant current source. 3, the FET can be used as an electronic switch. Second, FET test, pin junction type field effect transistor recognition: the gate of the FET corresponds to the base of the transistor, source and drain correspond to the emitter and the collector of the transistor. The multimeter R × 1k file, along with the two leads were used to measure positive and negative resistance between two pins each. When positive and negative resistance between two pins equally certain, both the number of KΩ, then these two pins for the drain D and source S (interchangeable), and the remaining one pin is the gate G . For JFET CJ78L05 4 pins, the other pole is shielded pole. STP65NF06 IC Product rating industry standard C1 level: production by non-original, brand new unused, complete package (Note: some from the mainland, Taiwan or other overseas countries CJ78L05 supply products, in full accordance with the specifications of the original brand factory requirements Packing and packaging, functionally identical CJ78L05 parameters, and printed with the original brand manufacturer. uncertain quality. High reliability as good as the original authentic quality.). C2 level: brand new unused (Note: the same or similar product features, remove the original logo change for another product identification market collectively, the "alternatives."). D1: no packaging, used CJ78L05 prices, products pin no damage, are second-hand. May be re-packaged vendor (Note: Unplug directly from the old board, as some DIP, PLCC, BGA package can be directly unplugged or "junk."). D2: no packaging, are second-hand. May be re-packaged vendor (Note: Direct removed from the old board, the pin was cut short in such products may be post-processed, would have been cut short stretch or take a long pin) . PH600S280-48 CJ78L05, Jiangsu CJ78L05, 耀坤 technology provided by Nanjing 耀坤 Technology Limited. Nanjing 耀坤 Ltd. (www.njykkj888.com) strong, credible, in Nanjing, Jiangsu diode industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead Yaokun into the brilliant technology and you work for a better future!