Electrical circuits with crocodile II

10. Draw the following circuits:
a. Circuit with a 9-volt battery, a PTM push switch and two bulbs that shine at the same time when you push
the switch.
b. Circuit with a 9-volt battery, a general switch to turn everything on/off and a double throw switch to
select what is working: a motor or a buzzer
c. Circuit with a 6-volt battery and two PTM push switches, one of them used to turn on a bulb when you
push it, and the other to turn a motor on when you push it.
d. Circuit with a 9-volt battery, a PTB push switch and three bulbs that are switched off at the same time
when you push the switch.

11.  A short circuit is an accidental connection between the two terminals of an element. In the following circuit there is a shortcut in one of the bulbs. 

a.  Explain  what  will  happen  in  the  circuit  when  the  switch  is turned on.

 The first bulb doesn´t light because there is another path with no resistance where the current flows.

b.  What  would  happen  in  the  circuit  if  the  short  circuit  is eliminated?

Both bulb light, but get dimmer as there is more resistance in the circuit.

12.  Using a battery, a PTM push switch, a standard switch, a buzzer and a bulb, draw a circuit in which the buzzer sounds if we push the PTM push switch and the standard switch turns the bulb on/off. 

13.  Using a battery, a PTM push switch, a double throw switch, a motor and a bulb, draw a circuit in which the motor will work in one of the positions of the double throw switch, and in the other position the bulb will light if the push switch is also pushed. 

16.  Using a battery and three bulbs, draw a series circuit and a parallel circuit, and answer the following questions: 

a.   How can we know that a circuit is series or parallel?

Series: The current that flows across each component is the same and the voltage of the supply is shared between the components.

Parallel: The voltage across each component is the same and the current is shared between each component.
  

 

b.   What happens in each of them if one of the bulbs blows out? Why?

Series: the others bulbs will not light because the circuit will be opened.

Parallel: the others bulbs will light because both paths are closed.

c.   Adding a switch to the circuits, can we switch only one of the bulbs on/off in each of the two
circuits? Why?

Series: no, because in a series circuit we have only one path to let current flows.

Parallel: yes, because in a parallel circuit we have independent paths to let current flows.

d.   In which one the circuits will the bulbs light brighter? Why?

In the parallel circuit because all the bulbs have the same voltage: 9V and in the case of the series circuit the bulbs have to share the voltage.




(These activities are adapted from a document by Manuel Torres. You can get it in
http://elprofesormanuel.wordpress.com/2011/01/27/crocodile-clips-tecnologia-3%C2%BA-e-s-o/ )