Having problems with relays!!!

guys i need help.. my relay doesnt change contacts...

i followed the tutorials in making a circuit with relay

i use a 5volts relay
bc548 npn transistor
1k resistor
and a diode parallel with the coil of relay...

the problem is... when i try to read the voltage readings across the relay it is only 1 or 2volts...
i also try putting a different transistor like ksp2222a... still i got the same results...

i connect the output of arduino series with a 1k resistor to base of transistor and emitter to ground and collector to coil of relay parallel with a diode then connected to 5volts supply from arduino...

help me pls

when i try to put higher dc voltage like 10volts instead of 5volts of arduino the transistor is getting very hot
and still got the same results...

You want to hook your relay up as shown

It sounds like you have the diode backward