7905 voltage regulator

[redhat]

i have connected the regulator as shown in the attached figure.the input is taken from an adaptor,the +ve terminal of the adaptor is connected to the gnd of 7905 and the -ve is connected to the input, the output is the voltage between the output pin and the gnd pin but i have an output of -1.5v although the input is 12v, is this connection right or should i use a center tapped transformer to have negative voltage.
regrads

 

[IanP]

voltage regulator 7905

The configuration is right; you don't need centre tap .. just (-) to input and (+) to GND. Try to connect capacitors between input-gnd-output-gnd and a load of, say, 100Ω - 1kΩ. If you still read this low voltage then your IS is "kaput" (faulty) ..

Added after 5 minutes:

Thing I've forgotten to mention, not like in 7805 where the body is the GND, in 7905 the metal thing is actually the input potential. You have to isolate it from everything ..