ECD2601
Assignment 1
DUE: 13 APRIL 2026
, UNIVERSITY OF SOUTH AFRICA
School of Engineering
Continuous Assessment – Assignment 1
ECD2601: Engineering Graphics for Electrical Design Project
Due Date: 13 April 2026
Total Marks: 50 | Weight: 15%
Examiner: Mr D Nagana | Internal Moderator: Mr C. Shoba
, Question 1 [20 marks]
1.1 EasyEDA Circuit Design – Forward Diode Model (5 marks)
The circuit below (Figure 1) was reproduced in EasyEDA. It consists of a DC voltage source
VBIAS = 15 V, a limiting resistor RLIMIT = 1.0 kΩ, and a silicon diode connected in a series
forward-biased loop.
Steps followed in EasyEDA:
• Open EasyEDA (online) and create a new schematic.
• Place a DC Voltage Source and set the value to 15 V.
• Place a Resistor component and set the value to 1.0 kΩ.
• Place a Diode (default silicon, 1N4007 or equivalent).
• Connect all components in series: positive terminal → R LIMIT → Anode → Cathode →
GND.
• Add ground symbols to both the negative terminal and the cathode node.
(Screenshot of EasyEDA schematic to be inserted here as per submission requirement.)
1.2 Calculation of Vᴹ, Iᴹ and Vᴹᴸᴸᴹᴵᴼ (10 marks)
Given values: VBIAS = 15 V, RLIMIT = 1.0 kΩ = 1000 Ω, r′d = 15 Ω (for complete model).
Model 1: Ideal Diode Model (Vᴹ = 0 V)
The diode is treated as a perfect short circuit – zero voltage drop.
IF = VBIAS / RLIMIT
IF = 15 V / 1000 Ω = 0.015 A = 15 mA
V_RLIMIT = IF × RLIMIT = 0.015 × 1000 = 15 V
Parameter Formula Value
VF Ideal model assumption 0V
IF VBIAS / RLIMIT 15 mA
V_RLIMIT IF × RLIMIT 15 V
Model 2: Practical Diode Model (Vᴹ = 0.7 V, Silicon)
A fixed barrier-potential voltage drop of 0.7 V is assumed for a silicon diode.
Assignment 1
DUE: 13 APRIL 2026
, UNIVERSITY OF SOUTH AFRICA
School of Engineering
Continuous Assessment – Assignment 1
ECD2601: Engineering Graphics for Electrical Design Project
Due Date: 13 April 2026
Total Marks: 50 | Weight: 15%
Examiner: Mr D Nagana | Internal Moderator: Mr C. Shoba
, Question 1 [20 marks]
1.1 EasyEDA Circuit Design – Forward Diode Model (5 marks)
The circuit below (Figure 1) was reproduced in EasyEDA. It consists of a DC voltage source
VBIAS = 15 V, a limiting resistor RLIMIT = 1.0 kΩ, and a silicon diode connected in a series
forward-biased loop.
Steps followed in EasyEDA:
• Open EasyEDA (online) and create a new schematic.
• Place a DC Voltage Source and set the value to 15 V.
• Place a Resistor component and set the value to 1.0 kΩ.
• Place a Diode (default silicon, 1N4007 or equivalent).
• Connect all components in series: positive terminal → R LIMIT → Anode → Cathode →
GND.
• Add ground symbols to both the negative terminal and the cathode node.
(Screenshot of EasyEDA schematic to be inserted here as per submission requirement.)
1.2 Calculation of Vᴹ, Iᴹ and Vᴹᴸᴸᴹᴵᴼ (10 marks)
Given values: VBIAS = 15 V, RLIMIT = 1.0 kΩ = 1000 Ω, r′d = 15 Ω (for complete model).
Model 1: Ideal Diode Model (Vᴹ = 0 V)
The diode is treated as a perfect short circuit – zero voltage drop.
IF = VBIAS / RLIMIT
IF = 15 V / 1000 Ω = 0.015 A = 15 mA
V_RLIMIT = IF × RLIMIT = 0.015 × 1000 = 15 V
Parameter Formula Value
VF Ideal model assumption 0V
IF VBIAS / RLIMIT 15 mA
V_RLIMIT IF × RLIMIT 15 V
Model 2: Practical Diode Model (Vᴹ = 0.7 V, Silicon)
A fixed barrier-potential voltage drop of 0.7 V is assumed for a silicon diode.
