# Thermal Runaway

The maximum power dissipation in a transistor depends on transistor construction and may lie in the range from few mW to some Watts. The power dissipated in a transistor is predominantly the power dissipated at its Collector Base junction. Thus the maximum power dissipated at Collector base junction is limited by the temperature that can … Continue reading Thermal Runaway

In general, the miller theorem is used for converting any circuit having the configuration of figure 2.48 (a) to another configuration shown in figure 2.48 (b) If $latex Z &s=2 &bg=ffffff$ is the impedance connected between two nodes, node 1 and node 2, it can be replaced by the two impedances $latex Z_1 &s=2 &bg=ffffff$ and $latex … Continue reading Millers Theorem # Signal Variation SIGNAL VARIATION >> It is the maximum or peak change in the value of voltage and current with respect to DC value. >> Based upon the value of signal variation, amplifier can be divided into two types. (i). Small Signal Amplifier (ii). … Continue reading Signal Variation # Biasing of BJT >> Biasing refers to providing appropriate DC voltage and DC current to an electronic device to operate it in a desired way. >> A BJT is biased due to following reasons : (i). To operate the BJT in active region, so that it can be used as an amplifier. (ii). To maintain the collector current … Continue reading Biasing of BJT # Stability Factors$latex \displaystyle \Rightarrow &s=2 &bg=ffffff$Stability factor indicates the degree of change in operating due to variation in temperature. There are three variables which are temperature dependent. We can define three stability factors :$latex \displaystyle S = \frac {\partial I_{C}}{\partial I_{CO}} \rightarrow \beta, V_{BE} &s=2 &bg=ffffff$Constant$latex \displaystyle S^{'} = \frac {\partial I_{C}}{\partial V_{BE}} \rightarrow … Continue reading Stability Factors
>> Two important factors are two be considered while designing the biasing circuit which is responsible for shifting the operating point ($latex V_{CE}, I_{C} &s=2 &bg=ffffff$). TEMPERATURE Variation in ICO: The flow of current in the circuit produces heat at the junctions. This heat increases the temperature at the junctions. >> Minority carriers are temperature … Continue reading Variation of Operating Point