A few questions to you first, to get an idea as to what you want to do, and
what you've done so far.

Are you trying to make a DC power source or an AC source?
Is the load the relay coil or a load that is being switched by the relay?
What kind of instrument are you using to measure the current, and how are
you hooking it into the circuit?
Is the relay a DC or AC relay? DC and AC relays are built differently, so
they have different characteristics.
If it's a DC relay coil, then just measure the coil resistance, divide that
value into the voltage across the coil and you'll know what the current
should be.
If it's an AC relay coil, then you really need the Mfr's specs to know how
much current the relay coil will draw. It's not just the coil's DC
resistance that determines the current; also the coil inductance.

Cheers,
Dave M


wrote:
Please I have to make a transformerless power supply using a
capacitor. I have made the circuit and its working well, my problem
is how to measure the current when its on load and the no-load
current. When I use the normal way of measuring current the meter is
not stable at all.
Please how do l do it. Also for academic purpose how do I calculate
the current drawn by the load (the load is a relay)
What are the advantages of using the transformerless PSU(using a
capacitor)
thanks