Just a quick question. I was building a regulated dual rail PSU +15V 0 -15V (1.25A each rail) for a modular synthesizer system.
I looked up some schematics, and people tend to use regular center tapped transfo's for this task.
From what I understand about transformers, I could also just use a toroidal 2x 18V transformer instead (Ringkerntransformatoren 230 V~ 2 x 18 V 50 VA Sedlbauer in de Conrad online shop | 518662).
By correct wiring, I could then create a single "center tapped" transfo equivalent - without adjusting the circuit.
Am I correct? Just want to make sure before I order.
I looked up some schematics, and people tend to use regular center tapped transfo's for this task.
From what I understand about transformers, I could also just use a toroidal 2x 18V transformer instead (Ringkerntransformatoren 230 V~ 2 x 18 V 50 VA Sedlbauer in de Conrad online shop | 518662).
By correct wiring, I could then create a single "center tapped" transfo equivalent - without adjusting the circuit.
Am I correct? Just want to make sure before I order.
Yes, just connect the two windings in series. When you do you have to make sure the windings are phased correctly. They should be labelled but if there is doubt just power it up with a bulb tester in the primary and connect the secondaries to a bridge and reservoir caps. If the voltages are OK its right, if not reverse the connections of one winding.
Ok, thank you!
I suspected that the phasing should be correct, but I can figure it out with a scope.
I suspected that the phasing should be correct, but I can figure it out with a scope.
You don't need a scope.
You need a mains bulb tester and an AC voltmeter.
Use the bulb tester to safely power ON the transformer.
Measure the voltage across each winding (keep them open circuit). It's safest to terminate each tapping into separate receptacles of an insulated terminal strip.
Power down.
Series connect the secondaries.
Power ON via the bulb tester.
Is the series secondary AV voltage the sum of the two individual secondary voltages?
If yes then they are in phase.
Power OFF.
Connect the rectifier.
Power ON and is the bulb still OFF?
Power OFF
Connect the smoothing capacitor/s.
Power ON and is the bulb still OFF?
You need a mains bulb tester and an AC voltmeter.
Use the bulb tester to safely power ON the transformer.
Measure the voltage across each winding (keep them open circuit). It's safest to terminate each tapping into separate receptacles of an insulated terminal strip.
Power down.
Series connect the secondaries.
Power ON via the bulb tester.
Is the series secondary AV voltage the sum of the two individual secondary voltages?
If yes then they are in phase.
Power OFF.
Connect the rectifier.
Power ON and is the bulb still OFF?
Power OFF
Connect the smoothing capacitor/s.
Power ON and is the bulb still OFF?
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