The video introduces the three circuit elements for investigation: a resistor, a light bulb, and a diode. It details how to connect a basic resistor circuit on a breadboard, powered by a 9V battery, including a switch and a 'control resistance' to vary potential difference and current to the circuit element being studied.

The control resistance can consist of single, series, or parallel resistors. Examples are provided for connecting three resistors in series and three in parallel, emphasizing the importance of correct connections for proper circuit functionality.

Instructions are given for measuring potential difference (voltage) across a circuit element using a multimeter in voltmeter mode. For current measurement, it's crucial to set the multimeter to ammeter mode and create a gap in the circuit to insert the ammeter in series, cautioning against incorrect connections that could damage the ammeter.

The light bulb circuit is described as similar to the resistor circuit, with the light bulb replacing the resistor. The procedure for measuring potential difference and current through the light bulb also follows the same principles, requiring a circuit gap for current measurement.

The diode circuit includes a switch, control resistance, and the diode itself. The video explains diode polarity (forward direction) and also how to connect an LED. A potentiometer is introduced as part of the control resistance, with a detailed explanation of its three pins and how its dial adjusts resistance from minimum to maximum.

The process for measuring potential difference and current in the diode circuit mirrors the previous methods, re-emphasizing the need for a multimeter in voltmeter or ammeter mode and creating a gap for current measurement.

A comprehensive list of steps is provided for filling each row of data tables for all three circuits. This includes connecting appropriate control resistance, turning on the switch, performing voltage and current measurements, reversing circuit element polarity, and then repeating measurements before turning off the switch and multimeter.

For the diode, two separate tables are used: one for the forward direction and one for the reverse direction. This approach is recommended to prevent frequent polarity changes, which could accidentally damage the diode with incorrect resistance settings.