1. Zenor Diode Diode Applications
ES230
Jack Ou

2. c03f01 The Design of a Cell Phone Charger Still need to be filtered to
get a DC voltage
Output of the transformer

3. c03f02
Short for Positive Voltages and
Open for Negative Voltages

4. c03f03 Behavior of Ideal Diode Ideal diode:
Vanode>Vcathode: Diode is on
Vanode<Vcathode: Diode is off
An ideal current experieincing Vanode=Vcathode, carries no current

5. c03f05 I/V Characteristics A short An Open A diode
Vanode>Vcathode: Diode is on
Vanode<Vcathode: Diode is off
An ideal current experieincing Vanode=Vcathode, carries no current
In practice, consider a slightly positive or negative voltage to
determine the response of a diode.

6. c03f07
Example 1

7. c03f08
Example 2: An OR Gate Realized By Diodes

8. In Class Exercise

9. c03f09
Example 3
c03f09

10. c03f10 A Simple Cell Phone Charger Circuit (R1 is necessary)
Another Application:
Signal strength indicator

11. Rectifier Circuit as Signal Strength Indicator

12. c03f11
A Limiter Circuit
Question: How do you modify this circuit so that it passes only
Positive portion of the waveform?

13. c03f13
Different Models of a Diode

14. Choosing a Diode Model
Use the ideal model to develop a quick, rough understanding of a circuit.
If the ideal model is not adequate, uses the constant voltage model, which is
sufficient for most cases.
Occasionally, we will use the exponential model

15. c03f14
Ideal Model versus Constant-Voltage Model

16. c03f15
Express ID1 and ID2 as a function of IS1, IS2 and Iin.