Hi, I'm using a 36V center tap transformer rated at 3A.
I need to obtain +15V and -15V dc for a current sesnsor.
I'm using a 7815 and 7915 for the +15Vdc abd -15Vdc respectively,also 7805 for +15Vdc.
Does anyone have a circuit design that may be able to help me.If you have any tips please tell me.
You might need to watch the power dissipation on the 7805 - it is running with a big voltage drop, probably about 17V. How much current do your supplies need?
For the supply of a sensor and then 100mA @ 5V yopu can use one 18V transformer and 1 diode (half wave rectification) for each rail (+ and -) connected to top transformer secondary winding, the bottom becomes your 0V. Use smoothing capacitors >1000µ per rail. After rectification with caps connected you will have 18V * 1.4 ≈ (+/-)25V (with no load). For currents as you described it should work ..