Begs the question, what V value are you measuring ? We are assuming
that you have a relatively large value cap on the output of the bridge,
so that AC is filtered out.
The 10V sinewave is +5V max to -5V min, so if there is no load on the
Cap/Bridge output then over a few sine cycles the cap charges to ~ 5V -
1 diode drop, or somewhere around 4.3 - 4.8 V. Thats if cap has low
leakage, and diode is nominally .7V when conducting. All this ignores
stray C coupling across diode, and other parasitics.
If using DVM, when you measure 10V sine, thats probably the average, or RMS,
unless it specifically has a peak reading capability. Compound this with the
frequency response of the meter probably only around 50 - 100 Khz, so good guess
you have >> 10V sine. Oscilloscope will give you better chance reading peak V.
Regards, Dana.