project2- resistor help

[ahuss]

Hi,
So im doing project 2 have a few questions.
1.I noticed that the 220 ohms resistors are placed after the leds towards the ground.
In the first project they were placed before the switch.
I thought the purpose of the resistors was to keep the LED's safe so shouldnt they be on the other side.

2. does the switch need protection from too much current. does it need a resistor. its the push button

3. I was freestyling a little using the switch in a similar way, as to project 2, however with this I placed the resistors before the leds and  removed the resistor between the switch and the ground.
For some reason once i put in anywire to the arduino input pin in this case 7 the leds lit up meaning that my program was read a voltage or current on the pin even though i cant figure out where it came from.
Thanks in advance for you help

[sh_aks]

1.I noticed that the 220 ohms resistors are placed after the leds towards the ground.
In the first project they were placed before the switch.
I thought the purpose of the resistors was to keep the LED's safe so shouldnt they be on the other side.

Resistor placed before of after LED in both cases the it will act as current limiter.

2. does the switch need protection from too much current. does it need a resistor. its the push button

- If the resistor is not there then every-time you press the switch you will connect 5v and GND. Thus shorting the power supply.
- To get proper 0 or LOW when you release the switch the Resistor has to be used as shown in Fig.2 of Chapter 2 of the book.

3. I was freestyling .....

Can you draw the image of the connection for better understanding.