Electronic Devices

Thermistor or Thermal Resistor is a two terminal semiconductor device whose resistance is a temperature sensitive.

When the anode terminal of a diode is connected to the negative terminal of voltage source and cathode to the positive terminal then the diode is reverse biased as shown in Fig. 1 (a) and its symbolic representation in Fig. 1 (b).

Figure 1. When anode is connected to the positive terminal of a battery/voltage source and cathode to the negative terminal, then the diode is said to be forward biased as shown in Fig. 1 (a) and its symbolic representation is shown in Fig. 1 (b).

Figure 1: V-I Characteristics of a PN Junction Diode. VI Characteristics of pn junction diode, is a graph between the voltage applied across the terminals of a device and the current that flows through it. Fig. 1 shows the V-I characteristics of a typical PN junction diode with respect to breakdown voltage (VBR). The complete V-I

Strain gauge is a resistive type transducer which converts change in mechanical displacement into a proportional change in resistance. It is the most commonly used method of displacement measurement.

It is possible to apply more than one input signal to an inverting amplifier. This circuit will then add all these input signals to produce their addition at the output. Such a circuit will then be called as an adder or a summing amplifier.

The voltage gain of the Voltage Follower (Buffer) circuit is 1 i.e. the output voltage will be equal to and in phase with the input voltage. In other words, the output voltage follows the input voltage. Hence the name voltage follower. Thus voltage follower is a non-inverting amplifier with a voltage gain of unity. Figure

In Inverting Amplifier, the amplified output signal will be 180º out of phase with the input signal. In other words the output signal is “inverted” as shown in Fig. 2. Therefore this amplifier is known as the inverting amplifier. Figure 1: Inverting Amplifier.

The phototransistor is an optoelectronic device that generates or detects the signals from light incident on it. The symbol of phototransistor is shown in figure (1).