Fundamental Of Electronics

Prof. Dr. Fahmy El-khouly

Chapter 2

Diode Applications

SERIES DIODE CONFIGURATIONS WITH DC INPUTS

Determine I , V1 , V2 , and Vo for the series dc configuration of Fig. 2.27.

Determine ID , VD2, and Vo for the circuit

.

PARALLEL AND SERIES–PARALLEL CONFIGURATIONS

Determine Vo, I1, ID1, and ID2 for the parallel diode configuration

Determine the voltage Vo for the network

Determine the currents I1, I2, and ID2 for the network

.

AND/OR GATES

Determine Vo for the network of Fig. 2.38.

Determine the output level for the positive logic AND gate of Fig.

2.41.

SINUSOIDAL INPUTS; HALF-WAVE RECTIFICATION

(a) Sketch the output Voand determine the dc level of the output for the network

of Fig. 2.48.

(b) Repeat part (a) if the ideal diode is replaced by a silicon diode.

(c) Repeat parts (a) and (b) if V is increased to 200 V and compare solutions

using Eqs. (2.7) and (2.8).m

FULL-WAVE RECTIFICATION

1-Bridge Network

Center-Tapped Transformer

Determine the output waveform for the network of Fig. 2.63 and calculate the

output dc level and the required PIV of each diode.

PIV is equal to the maximum voltage

across R, which is 5 V

CLIPPERS

When diode “on” Vo =Vi - Vdc

When diode “off” Vo= 0

Example 1

*At –ve half cycle diode is “off” then Vo=0

*At +ve half cycle there are two periods:

(i) Vi<Vdc then diode “off” and Vo = 0

(ii) Vi > Vdc then diode “on” and Vo = Vi-Vdc

Example 2

*At +ve half cycle diode is “on” then Vo=Vi+Vdc

*At -ve half cycle there are two periods:

(i) [Vi]<[Vdc] then diode “on” and Vo = Vi+Vdc

(ii)[ Vi ]> [Vdc] then diode “off” and Vo = 0

Example 3

Example 4

When diode is “on” then Vo = Vdc

When diode is “off” then Vo = Vi

At –ve half cycle diode is “on” then Vo = Vdc

At +ve half cycle there are two periods:

(i) Vi<Vdc then diode “on” and Vo = Vdc

(ii) Vi > Vdc then diode “off” and Vo = Vi

CLAMPERS

After the capacitor charged with Vc=+Vi then the diode is always “off”

and Vo=Vi-Vc

Example

After the capacitor charged with Vc=+Vi +Vdc

then the diode is always “off”

and Vo=Vi+Vc

ZENER DIODES

Zener diode equivalents for the (a) “on” and (b) “off” states