A simple voltage divider circuit can be constructed as shown, using just two resistors connected across a voltage supply. Current I will flow through R1 and R2 determined by their combined value. The lower voltage (Vout) across R2 is found by Ohm's Law I × R2. Circuits connected to the Vout junction are referred to as the Load. Load current will flow through R1 in addition to R2 current and effectively pull down the voltage at this junction due to the increased voltage drop across R1. TEST YOUR UNDERSTANDING: This assignment explores circuit voltages a little further by showing what happens when we connect a load across a voltage supply. It's known that electricity generating companies have to account for this during the commercial breaks in popular television programmes i.e. sport, when large numbers of people switch on their kettles at the same time, thereby placing a heavy load on the electricity supply causing the voltage to drop and if not corrected by enabling more current to flow would dim the lights. Returning to your plugboard construct each of the circuits and vary the load from light (10k) to heavy (10R) whilst measuring the voltage across R2. Using a plugboard is not essential in any of these experiments, but it does give you a practical feel for what Is occurring. Providing the battery can supply the current what is happening to the voltage across R1 for each of these conditions? Understanding this effect is again important and like Ohm' Law fundamental to the study of electronics.
