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Is a variable resistor analog or digital?
Digital potentiometers are digitally controlled variable resistors that can be used in place of their functionally equivalent mechanical counterparts. Potentiometers can be used to adjust voltages or currents by varying the resistance of the device.
Where can we find variable resistor?
As the resistive material is required, a carbon film type of variable resistors is generally used. They find applications in the radio receiver circuits, audio amplifier circuits, and TV receivers.
What do you mean by variable resistance?
Variable resistance is a device used to change the resistance and hence the current flowing through a circuit; without changing the voltage.
What is difference between rheostat and variable resistance?
A rheostat is a variable resistor used to control current by varing the resistance . It can be used to control downstream devices like transistors,dimmer switches etc. Variable resistor is an electrical component used to vary the amount of current that flows through the circuit.
When is the transistor operating in the saturation region?
In Fig. 6B, with negligible gate current VGS= VDS so that the transistor is operating in the saturation region. When it is required that VGS ≠ VDS, the circuit in Fig. 6C may be used. As in the BJT case, in most amplifier applications RS is paralleled by a capacitor.
When is the base resistor in hard saturation?
Your circuit might be TTL and feeding 5-V, or perhaps CMOS, feeding 3.3-V. In this example, to make the maths simple, let us say that the switching voltage is 10-V at the input. When the transistor is in hard saturation, the entire switching voltage (10-V), will be effectively across the base resistor.
What is the resolution of a variable resistor?
A variable resistor with a resolution 0.005 means, that the smallest value by which the resistance changes is 0.005 ohm. A high resolution is a favourable characteristic of a variable resistor. Now that we have discussed the main characteristics of the variable resistor, let’s now have a look into the types of variable resistor.
How to calculate base resistance of a transistor?
Therefore, with simple transposition of the above formula, the following formula provides the base resistance: Rb = (Vi – Vbe) / Ib. To guarantee that the transistor operates in the saturation region, we multiply the base current by a factor of three.