Conrad Course material 10025 14 years and over 10025 Manual De Usuario

 
Unplug a connection of the solar module. What happens? The LEDS no longer shine. Plug it in again 
– the LEDs shine again. 
 

5. 

Step: Series and parallel connection 

Experimental set-up: solar module, patch panel, red, green and orange LEDs, two 100 Ω resistors 
 

This experiment also works with little light (cloudy sky). 

 
Fig. 18: a) Principle behind series connection of individual solar cells; b) string of crystalline cells with 
connections of individual solar cells by means of flat connectors. 
 
The principle of series and parallel connection can be studied with the help of LEDs. 
 
Series connection of solar cells as it was done in the case of the module included in the educational 
kit: 

• 

The voltages are added when solar cells are connected to one another in series. 

• 

The short circuit current corresponds to that of a single solar cell – i.e., to that of the 

weakest one (the weakest link in the chain). 

• 

If a solar cell is shaded, the output of the entire solar module drops by the degree of 

shading. 

• 

With partial shading of a cell, the illuminated solar cells feed their current into the shaded 

solar cell; the latter heats up and in an extreme case can be destroyed. 

• 

 

What does series connection mean? So as to be able to practically understand this, do the following 
experiment with the LEDs: 
 
Fig. 19: Insert the red and the orange-coloured (or green) LED in the patch panel so that both LEDs 
are connected in series. The longer connection wire of the LEDs is the positive pole. 
 
Fig. 20: The associated circuit diagram 
 
No series resistor has to be used with this set-up. How brightly do the LEDs shine?  
 
Individual solar cells (or solar modules) can also be connected electrically in parallel. In this case, all 
negative pole and all positive pole connections of the solar cells are connected to one another. The 
result: 

• 

The voltage of the solar cells connected in parallel corresponds to that of a single cell. 

• 

The short circuit current is increased by the amounts of current from the individual cells. 

With solar cells that are equally strong, the short circuit current is increased by the number of cells. 

• 

It is possible to connect cells together with different outputs (short circuit current). 

With partial shading of a cell, the illuminated solar cells feed the added current into the shaded cell. 
The latter heats up and can in an extreme case be destroyed.  
 
Fig. 21a: Parallel connection of several solar cells 
 
Fig. 21b: Parallel connection of two LEDs 

6. 

Step: Solar power with intermediate storage 

Experimental set-up: solar module, patch panel, 100 Ω series resistor, flashing LED, 4,700 µF 
electrolytic capacitor  
 

This experiment also works with little light (cloudy sky). 

 
Insert the flashing LED and the series resistor in the patch panel. 
 
Fig. 22: Circuit diagram: series resistor and flashing LED 
 
Fig. 23: Patch panel set-up