(Solved): Diode circuit Analysis: Series, Parallel, multiple diode circuits Reguired Reading: Text, ...

Diode circuit Analysis: Series, Parallel, multiple diode circuits Reguired Reading: Text, section 3.2.6 Objective: - To analyze series and parallel diode circuits. - To analyze circuits containing multiple diodes. Discussion: When a diode is connected as in Figure 1, it is forward-biased (FB), and it allows current to flow in the forward direction. The diode has a small voltage across it, allowing the majority of the source voltage to be across the load. Thus, the FB diode acts like a closed switch with a small voltage in series with it. If the source voltage's polarity is reversed, the diode becomes reverse-biased (RB), and it acts like an opened switch and it drops all of the source's voltage across the diode leaving none for the load. If a circuit contains multiple diodes and sources in the circuit, a state has to be assumed for each diode based on the orientation of each diode. Circuit analysis techniques such as mesh current analysis can be used to approximate the current in each diode. The power can also be determined. Pre-lab Assignment: None Materials: 1 DMM 1 Dual-polarity DC power supply 2 general purpose diodes 1 Resistor package 1. Consider the circuit shown Figure 1. The diode is \( \mathrm{SI} \). Figure 1 Record the measured values of resistors. \( \mathrm{R}_{-1.8 \mathrm{k} \Omega \text {-meas }}= \) \( \mathrm{R}_{-1 \mathrm{k} \Omega \text {-meas }}= \) a. Build the circuit shown Figure 1. b. Use a DMM to measure \( I_{D}, V_{-1.8} \mathrm{k} \Omega, V_{D} \), and \( V_{0} \). Note: \( V_{0}=V_{-1 k \Omega} \). \( I_{D}= \) \( V_{-1.8} \mathrm{k} \Omega= \) \( \mathrm{V}_{D}= \) \( \mathrm{V}_{0}= \) 2. Consider the circuit shown Figure 2. The first diode is \( \mathrm{SI} \), and the second is \( \mathrm{Ge} \). Figure 2 a. Build the circuit shown Figure 1. b. Use a DMM to measure \( I_{D}, V_{-1.8} \mathrm{k} \Omega, V_{D} \), and \( V_{0} \). Note: \( V_{0}=V_{-1 k \Omega} \). \( I_{D}= \) \( \mathrm{V}_{-1.8 \mathrm{k} \Omega}= \) \( V_{D}= \) \( \mathrm{V}_{0}= \) 3. Consider the circuit shown Figure 3. The diode is SI. Figure 3 Record the measured value of the second \( 1 \mathrm{k} \Omega \) resistor. The other resistors were measured earlier. \( \mathrm{R}_{-1} \mathrm{ksomeas}= \) a. Build the circuit shown Figure 3 . b. Use a DMM to measure to and \( V_{0 .} \). Note: \( V_{0}=V_{\text {. the. }} \) (Connected to the output terminals) \( \mathrm{I}_{0}= \) \( V_{0}= \) c. Replace the \( 1 \mathrm{k} \Omega \) in series with a short (a wire) and repeat Procedure \( 3 \mathrm{~d} \). \( t_{0}= \) \( V_{0}= \) 4. Consider the circuit shown Figure 3. Figure 4 Measure the resistor values of Fig. 4. Then construct the network. Use only Si diodes. \( \mathrm{R}_{100 \Omega}=\Omega \quad\left(1^{\text {st }}\right. \) one in series with the \( 8 \mathrm{~V} \) source \( ) \) \( R_{510 \Omega}= \) \( \Omega \) \( R_{820 \Omega}= \) \( \Omega \) \( \mathrm{R}_{100 \Omega}= \) \( \Omega \quad\left(2^{\text {nd }}\right. \) one in series with D4) Measure and record the currents through each diode. c. Measure and record the voltages across cach diode. \( V_{D 1}= \) V, \( \quad V_{\mathrm{D} 2}= \) \( \mathrm{V}_{\mathrm{D} 3}= \) V. \( V_{D 4}= \) Questions 1. Consider Procedure 1. a. How did the calculated and measured values compare? How do you take into account any differences? b. Using your calculated values from the pre-lab, how much power was dissipated in the following? \( P_{0}= \) (In \( 1 \mathrm{k} \Omega \) resistor) \( P_{D}= \) (In Diode) Consider Procedure 2. How do the calculated and measured values compare? How do you take into account any differences? 3. Consider Procedure 3 a. How do the calculated and measured values compare? How do you take into account any differences? b. Using your calculated values from the pre-lab, how much power was dissipated in the \( 1 \mathrm{k} \Omega \) resistor load? \( \mathrm{P}_{0}= \) 4. Consider Procedure 4. How do the calculated current values compare with the measured values? Which of the diodes are forward biased? Which of the diodes are reverse biased? Comment on the current value(s) of the RB diode(s).