[R-390] PTO heaters

[Paul Galpin]

They said......


 "Of course, 9VDC isn't the same as 9V RMS .........."


Yes, it is exactly the same! The definition of the RMS value is "That value
of an alternating voltage (or current) which gives the same heating effect
as a DC voltage (or current) of the same value" For a sine wave, which is
what should be coming out of your wall socket or transformer, the RMS
voltage is 0.707 of the peak value (For other wave shapes, this value is
different)
Even connecting your 9V battery directly across the valve heaters will
probably do no harm as the small 9V battery will quickly run down trying to
give 300mA!

Paul Galpin
ZS2PG