1. The 2N4915 is an NPN Silicon Amplifier Transistor with high breakdown voltage, high gain, low noise, and low leakage current. It is designed for amplification of small signals in critical circuits, such as high-frequency hybrid amplifiers, broadband circuits, and differential amplifiers.
2. It has a maximum gain of 1000, making it well-suited for circuits which require high magnification of asciall signals. The low noise level of the 2N4915 ensure that signals of interest can be clearly distinguished from background noise, and the low leakage current ensures that the transistor will not hog power from the circuit.