Dave Jones discusses the need for electronic loads in power supply testing and the basics of building one.

• Dave Jones highlights the frequent need to design switch mode power supplies for projects.
• He emphasizes the importance of characterizing power supply performance across the load range.
• An electronic load is introduced as a tool to simulate different load conditions for testing.

Dave constructs a simple electronic load using junk box components and explains the design choices.

• Dave decides to build an electronic load using available components such as an N-Channel MOSFET and an LM324 opamp.
• The load functions as a constant current sink with a 10-turn potentiometer for precise control.
• The design includes a panel meter for direct current readout, eliminating the need for an external multimeter.

Dave elaborates on the electronic load design, including the MOSFET characteristics and the voltage follower circuit.

• Dave selects a logic level MOSFET (MTP 305) and uses an LM324 opamp as a series pass transistor in the design.
• The MOSFET's characteristic curve is examined to understand the voltages required for different load currents.
• Dave explains the use of a voltage follower opamp and voltage divider to manage the input voltage for the load.

Additional design aspects, such as fine-tuning and adding a panel meter to the load, are covered.

• A 10-turn potentiometer allows for fine control of load current from 1mA to 1A.
• The panel meter is introduced, which can display the set current up to 2A, simplifying power supply testing.
• Precision resistors are used in the input of the panel meter for accurate current measurement.

Discussion on heat sink selection and power dissipation calculations for the electronic load.

• Dave calculates the power dissipation in the heat sink based on the input voltage and the load current.
• He provides a real-world example to check the temperature rise of the heat sink using a temperature probe.
• The results confirm the back of the envelope calculations for heat sink performance.

Dave concludes with final thoughts on the electronic load's capabilities and potential applications.

• The electronic load is capable of handling a range of currents, limited by the specifications of the MOSFET and heat sink.
• Dave demonstrates the load's performance by showing it can handle currents from 1.5mA to 1.35A.
• The versatility of the load is highlighted, showing its potential for creating efficiency graphs for power supplies.

Exploring how a microcontroller can extend the functionality of the electronic load.

• Adding a microcontroller can turn the simple load into an intelligent system capable of various load simulations.
• The microcontroller enables constant current, constant power, constant resistance, and pulse load testing.
• Such an advanced system can be used to generate detailed performance graphs for batteries and other devices.