At its name indicates, this MOSFET operates only in the enhancement mode & has no depletion mode. It works with large positive gate voltages only. It differs in construction from the DEMOSFET in that structurally there exists no channel between the drain & source” which shown in figure below. Hence it does not conduct when VGS=0 i.e. why… Read More »
The voltage gain of an amplifier varies with signal frequency due to the effect of variations in circuit capacitive reactance with signal frequency in the output. The curve drawn between the voltage gain and signal frequency of an amplifier is known as the frequency response. If the input voltage is kept constant but its frequency is varied, it… Read More »
Class B amplifier is a type of power amplifier where the active device (transistor) conducts only for half cycle obey input signal. That means the conduction angle is 180 degree for a class B amplifier. Since the active device is switched off for half the input cycle, the active device dissipates less power hence the efficiency is improved.… Read More »
OP-AMP Bandwidth, frequency response & gain bandwidth product are key parameters for any circuit. Typically, OP-AMPs are used for comparatively low frequency circuit but with the performance of these chips is improving all the time, much higher bandwidth OP-AMPs are available. The frequency response response of a typical OP-AMP chip will often start to fall at a very… Read More »
JFET as an amplifier- The weak signal is applied between gate and source, and amplified output is obtained across drain and source terminal. For proper operation of JFET gate must be negative with respect to source. Input circuit should always be reversed biased with help of a battery Vgg or by a circuit is known as biasing circuit.… Read More »
Depletion type MOSFET- A slab of P type materials formed from a silicon base and refer towards substrates. It is the foundation on which device is constructed. In some cases, substrates are internally connected to source terminal. The source and drain terminals are connected through metallic contacts to N-doped region linked by N-channel. The gate is also connected… Read More »
Working of JFET- The two P-N junctions at the sides form two depletion layers. The current conduction by charge carrier i.e. electrons in case of N-channel JFET is thought the channel between two depletion layers and out of drain. The width and hence resistance of this channel can be control by changing the input voltage Vgs. The greater… Read More »
BJT- Bipolar transistor Current conduction takes place due to both electrons and holes BJT has negative temperature coefficient BJT has high volt gain BJT has no current gain Low input impedance More noisy Larger in size Small current is required to keep the device ON It is less thermally stable It is a current control device Low frequency… Read More »