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DIODE TUTORIALS Ideal Diodes

1. What is the current through the diode and the voltage across the diode for the

following two circuits?

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2. What is the output voltage for the following circuit?

3. What is the voltage across the diode?

4. What is the voltage transfer characteristic ( ov vs. iv )?

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5. For the following circuit, if sv is a sinusoid with 24-V peak amplitude, find the

fraction of each cycle during which the diode conducts. Find the peak value of the

diode current and the maximum reverse-bias voltage that appears across the

diode.

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6. Analyze the following circuits assuming that the voltages are either 0V or 5V.

What logic functions do they perform?

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7. Find I and V in the following circuits.

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8. Find the values of I and V in the following circuits.

9. Find the values of I and V in the following circuits.

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Diode Models

1. Determine the current DI and the diode voltage DV for the following circuit with

5DDV = V and 1R = kΩ . Assume that the diode has a current of 1 mA at a voltage

of .7 V and that its voltage drop changes by .1 V for every decade of change in

current.

2. Repeat Problem 1 using the piecewise linear model assuming

0 0.65V and 20D DV r= = Ω

3. Repeat Problem 1 using the constant voltage drop model.

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Diode Circuits & Zener Diodes

1. Design the following circuit to provide an output voltage of 2.4V. Assume the

diodes have a current of 1 mA at a voltage of .7 V and that its voltage drop

changes by .1 V for every decade of change in current

2. Consider the following circuit. What is the percentage change in the regulated

voltage caused by (a) a 10% change in the power-supply voltage and (b)

connection of a 1k load resistance?

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3. A 6.8-V Zener diode in the circuit below is specified to have Vz=6.8V at

Iz=5mA, rz=20 ohms, and Izk=0.2mA. The supply voltage is nominally 10V but

can vary by +/- 1V.

a. Find Vo with no load and with V+ at its nominal value.

b. Find the change in Vo resulting from the +/-1V change in V+. Note that

(Vo/ V+), usually expressed in mV/V, is known as line regulation.

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c. Find the change in Vo resulting from connecting a load resistance RL that

draws a current IL of 1mA, and hence find the load regulation (∆Vo/∆ IL),

in mV/mA.

d. Find the change in when 2O LV R k= Ω

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e. Find the change in when 0.5O LV R k= Ω

f. What is the minimum value of RL for which the diode still operates in the

breakdown region?

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Rectifiers

1. For the circuit below (Half-Wave Rectifier),

Draw the piecewise-linear model circuit.

Draw the i-v transfer characteristic.

Draw the input and output waveforms.

What is the Peak-Inverse Voltage (PIV) across the diode?

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2. For the circuit below (Full-Wave Rectifier), use the constant-voltage drop model.

Draw the i-v transfer characteristic.

Draw the input and output waveforms.

What is the Peak-Inverse Voltage (PIV) across the diodes?

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3. For the circuit below (Bridge Rectifier), use the constant-voltage drop model.

Draw the i-v transfer characteristic.

Draw the input and output waveforms.

What is the Peak-Inverse Voltage (PIV) across the diode?

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4. For the circuit below (Peak Rectifier), use the constant-voltage drop model.

Draw the input and output waveforms.

5. For the circuit below (Half-Wave Peak Rectifier with Load), use the constant-

voltage drop model.

Draw the input and output waveforms.