Relay

A relay is the device which uses a low ampereage circuit to switch on a higher amperage circuit.This is very common among vehicles and they are of various kinds but do the same sort of work.
First of all we measured resistance of the relay from
86 to 85 was 76.4 ohm
30 to 87a was 0 ohm
30 to 87 was 0 ohm
then we had to identify the the controling circuit and switching circuit.
the 86 to 85 is the contorlling circuit and 30,87and 87a r switching cause the resistance is bet 86 and 85
in a relay when the relay is off 30 to 87a is NORMALLY CLOSED and 30 to 87 is NORMALLY OPEN
then we made a circuit using a relay 3 bulbs and a 12v source in sucha way that all 3 r in parallel and when we turn the realy on the bulbs r on.

Then we made a circuit in whcih 2 bulbs were in parallel and 1 in series adn the relay alternatly turns them on off.