emitter bias

27,100,-60 1) Emitter-Bias: The dc bias network contains an emitter resistor to improve the stability level over that of the fixed-bias configuration.. The more stable a configuration, the less its response will change due to undesirable changes in temperature and parameter variations 2) Voltage Divider Bias: Configuration that can provide high bias stability is voltage divider bias. Instead of using a negative supply off of the emitter resistor, like two-supply emitter bias, this configuration returns the emitter resistor to ground and raises the base voltage. So as to avoid issues with a second power supply, this base voltage is derived from the collector power supply via a voltage divider. 3) Emitter Follower: emitter follower is one of three basic single-stage BJT amplifier which is used as a voltage buffer. In this circuit the base terminal of the transistor serves as the input, the emitter is the output, and the collector is common to both hence its name. The analogous field-effect transistor circuit is the common drain amplifier and the analogous tube circuit is the cathode follower. The low output impedance allows a source with a large output impedance to drive a small load impedance; it functions as a voltage buffer. In other words, the circuit has current gain instead of voltage gain, because of its characteristics it is preferred in many electronic devices. A small change to the input current results in much larger change in the output current supplied to the output load. 4) Common Base: The Common Base Amplifier is another type of bipolar junction transistor, (BJT) configuration where the base terminal of the transistor is a common terminal to both the input and output signals, hence its name common base (CB). The common base configuration is less common as an amplifier than compared to the more popular common emitter, (CE) or common collector, (CC) configurations but is still used due to its unique input/output characteristics. For the common base configuration to operate as an amplifier, the input signal is applied to the emitter terminal and the output is taken from the collector terminal. Thus the emitter current is also the input current, and the collector current is also the output current, but as the transistor is a three layer, two p n-junction device, it must be correctly biased for it to work as a common base amplifier. That is the base-emitter junction is forward-biased. Conclusion: This is how We can learn and understand Different Biases in BJT and We can Prove Their Formulas.