Examples of appliances that contain a rectifier: Radio, television, computer, battery charger, mobile phone charger. Demonstrating the action of a diode Use a light bulb in series with the semiconductor and the battery. Observation: Bulb lights when switch is closed (circuit is forward biased), but not when the diode is put in the other way around (reverse biased). The Light-Emitting Diode (LED) Image Symbol An LED consists of a junction diode made from semiconducting material. Light is emitted from the junction when it is forward biased and the brightness is approximately proportional to the forward current. Mandatory Experiments To investigate how Resistance changes with Temperature for a Thermistor To investigate the variation of Current with Potential Difference for a Semiconductor Diode Leaving Cert Physics Syllabus Content Depth of Treatment Activities STS Conduction in Conduction in semiconductors. Interpretation of graph. I–V materials References to charge carriers. Conduction in semiconductors: Electronic devices. the distinction between intrinsic LED, computers, and extrinsic conduction; integrated circuits. p-type and n-type semiconductors. The p-n junction: basic principles Demonstration of current Rectification of a.c. underlying current flow across a flow across a p-n junction p-n junction. in forward and reverse bias, e.g. using a bulb. LDR light-dependent resistor. Demonstration of LDR and – Thermistor. thermistor. TO INVESTIGATE THE VARIATION OF CURRENT (I) WITH P.D. (V) FOR A SEMICONDUCTOR DIODE IN FORWARD BIAS APPARATUS: Low voltage power supply, rheostat, voltmeter, ammeter, 330 semiconductor diode Ω resistor, DIAGRAM: PROCEDURE: 1. Set up the circuit with the semiconductor diode in forward bias as shown. 2. Adjust the potential divider to obtain different values for the voltage V and hence for the current I. 3. Obtain at least ten values for V and for I using the voltmeter and the ammeter. 4. Plot a graph of I against V and join the points in a smooth, continuous curve.
Examples of appliances that contain a rectifier: Radio, television, computer, battery charger, mobile phone charger. Demonstrating the action of a diode Use a light bulb in series with the semiconductor and the battery. Observation: Bulb lights when switch is closed (circuit is forward biased), but not when the diode is put in the other way around (reverse biased). Image Symbol The Light-Emitting Diode (LED) An LED consists of a junction diode made from semiconducting material. Light is emitted from the junction when it is forward biased and the brightness is approximately proportional to the forward current. Mandatory Experiments To investigate how Resistance changes with Temperature for a Thermistor To investigate the variation of Current with Potential Difference for a Semiconductor Diode Leaving Cert Physics Syllabus Content Depth of Treatment Activities STS Conduction in materials Conduction in semiconductors. References to charge carriers. Interpretation of I–V graph. Conduction in semiconductors: the distinction between intrinsic and extrinsic conduction; p-type and n-type semiconductors. Electronic devices. LED, computers, integrated circuits. The p-n junction: basic principles underlying current flow across a p-n junction. Demonstration of current flow across a p-n junction in forward and reverse bias, e.g. using a bulb. Rectification of a.c. LDR – light-dependent resistor. Thermistor. Demonstration of LDR and thermistor. TO INVESTIGATE THE VARIATION OF CURRENT (I) WITH P.D. (V) FOR A SEMICONDUCTOR DIODE IN FORWARD BIAS APPARATUS: Low voltage power supply, rheostat, voltmeter, ammeter, 330 Ω resistor, semiconductor diode DIAGRAM: PROCEDURE: 1. Set up the circuit with the semiconductor diode in forward bias as shown. 2. Adjust the potential divider to obtain different values for the voltage V and hence for the current I. 3. Obtain at least ten values for V and for I using the voltmeter and the ammeter. 4. Plot a graph of I against V and join the points in a smooth, continuous curve.
25-semiconductors.docx