Yes, the only output is an LCD interface, there is no electrical connection with the outside other than the AC mains input.
I considered measurement transformers, but size and cost are both critical design constraints for this project, and resistors beat transformers on both counts, hands down...
Hey all.
The resistors on the primary (R1,2,3) are just jumpers that allow the circuit to be configured for 120V or 240V while the transformer outputs 10VAC regardless.
The case is plastic, and has no electrical connection. The ground symbol in the schematic just means my board's ground plane...
Because the secondary voltage of the transformer is a function of the current draw, which is not constant, so measuring the voltage here could not give me the high accuracy I need.
Since my device has a 3-pronged plug, an improperly wired outlet is really the only way it could get plugged in...
Thanks IRstuff.
Part of my circuit (not shown) needs to know the AC voltage that is being applied to the board (this ia a power measurement device). That is done very simply by inserting a voltage divider across the AC live voltage and then into an A/D converter. But this forces me to tie my DC...
Hi,
I have a simple power supply circuit (please see: www.nangreaves.ca/ps.jpg). This circuit supplies 5V for the rest of my board. The PS input is AC line voltage. If someone were to plug my board into the wall socket backwards (switching hot and neutral) then my whole ground plane would...