I'm trying to measure 240V AC with a data acquisition box that will measure up to 10V. So I used a transformer to take it down to 6.3V AC and then a bridge rectifier and cap to make it DC. The voltage isn't what I expected because I'm get 240V AC = 8.58V DC. I was expecting240V to equal 8.9V (6.3 x 1.41). Is there something I am doing wrong? Should I have some sort of small load on this?
Thanks in advance, Michael