I'm building a dual power supply with outputs of 0 - 20V. Each supply comes from it's own secondary, see the barebones circuit below
The regulators (LM338 ed. PJL) and associated gubbins come from points A and C for each channel. However I want the outputs to have a common zero volts - as opposed to the separate points B and D. I need this as the power supply has a microprocessor controlled Voltage/Current display, which is run from just one of the channels, so 0V must be a common reference point for the A-D converters.
I'm apprehensive about just connecting these two points together as I have no information about the relative phases of the secondaries (i.e. whether they are connected as shown, with P1A - P1B and p2A - P2B, or with one secondary "reversed", relative to the other).
Measuring the voltage across B - D shows about 5 Vols A.C, but with a 1k resistor, this drops to zero. The transformer is spec'd at 100W, so if I get this wrong, big smoke is a definite possibility.
Simple question: can I safely connect the points B and D to form a common 0V for the two supplies?
Answered by sgtwookie - yes you can.
The regulators (LM338 ed. PJL) and associated gubbins come from points A and C for each channel. However I want the outputs to have a common zero volts - as opposed to the separate points B and D. I need this as the power supply has a microprocessor controlled Voltage/Current display, which is run from just one of the channels, so 0V must be a common reference point for the A-D converters.
I'm apprehensive about just connecting these two points together as I have no information about the relative phases of the secondaries (i.e. whether they are connected as shown, with P1A - P1B and p2A - P2B, or with one secondary "reversed", relative to the other).
Measuring the voltage across B - D shows about 5 Vols A.C, but with a 1k resistor, this drops to zero. The transformer is spec'd at 100W, so if I get this wrong, big smoke is a definite possibility.
Simple question: can I safely connect the points B and D to form a common 0V for the two supplies?
Answered by sgtwookie - yes you can.
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