108 – Add and subtract voltages

Interconnecting batteries  

Introduction to:  

Voltage concept, voltage measurement, properties of electric voltage, electric potential

Material:  

  • Voltmeter (DC voltage = DC, measuring range 0…5V).   
  • 1.5V batteries (3)    

Setup and execution:  

  • measure the voltage of a battery  
  • place two batteries together, negative pole to positive pole, and measure the voltage again  
  • add a third battery, again negative pole to positive pole, and measure the voltage again  
  • turn the third battery so that its positive pole is in contact with the positive pole of the second battery, and measure this voltage as well  

Observation:  

  • If we connect opposite poles, the individual voltages add up to the total voltage.  
  • In the last experiment, the voltage of the reversed battery subtracts from the sum of the voltages of the other two batteries  

Didactic potential:  

  Demonstration of voltage as potential difference