need some basic circuit assistance - capacitor / transformer stuff
need some basic circuit assistance - capacitor / transformer stuff
(OP)
If you have a high volage transformer 120vac to 2000vac then a 1/2 wave rectifier (diode) is in series to change to dc and then a large nonpolar capacitor that is in parallel with the item that it discharges to... is it ok to have the return to the other side of the capacitor? See attached sketch in the file.
Can someone explain to me what happens inside the capacitor to make this work without a connection to neutral or ground? Maybe the capacitor can reuse the leftovers? or does it connect to neutral somehow through the transformer... I'm trying to learn more about circuits so I appreciate any help.
Can someone explain to me what happens inside the capacitor to make this work without a connection to neutral or ground? Maybe the capacitor can reuse the leftovers? or does it connect to neutral somehow through the transformer... I'm trying to learn more about circuits so I appreciate any help.





RE: need some basic circuit assistance - capacitor / transformer stuff
Think of a torch battery. There is voltage between the terminals and you needn't connect to ground to make a lamp light.
Same thing with a transformer. Voltage (AC in this case) is induced in the secondary winding and that voltage is rectified in the diode and reaches the capacitor, which is charged. The resistor just loads the capacitor and there is a current flowing in it which discharges the capacitor when AC is removed from transformer primary.
Don't confuse yourself by using terms like 'leftovers' - no use.
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: need some basic circuit assistance - capacitor / transformer stuff
RE: need some basic circuit assistance - capacitor / transformer stuff
What if you connected a the bottom right terminal of the transformer to ground?
Thank you for your answers so far... very helpful
RE: need some basic circuit assistance - capacitor / transformer stuff
"Ground" is an arbitrary reference, there is nothing special about it. It is used because it is both convenient and operators are usually in contact with it making it a good choice for safety purposes. Whether or not the circuit shown in the diagram is safe will depend on a lot of factors that are not part of the diagram, especially those related to whether or not someone can come into contact with 'live' conductors, the supply voltage, fault current capacity, the operating conditions, and the mechanical design. By using a transformer, the secondary is no longer referenced to the same point as the primary and you are free to choose a new (and arbitrary) reference.
Often times when you have a form of "mains" circuit on the secondary of an isolated transformer, a ground is required and is established. If for example, this circuit is the power supply of an enclosed device, this is not done.
RE: need some basic circuit assistance - capacitor / transformer stuff
Grounding something in your car, or even in an aircraft !! still applies.
It just means connecting one side of something to the main local mass of wherever the equipment is located, usually for both convenience and safety.
But something operating from a small battery is often completely isolated and not grounded to anything.
RE: need some basic circuit assistance - capacitor / transformer stuff
John D
RE: need some basic circuit assistance - capacitor / transformer stuff
???
An iPod Touch (an example that uses a capacitive touch screen) works on airplanes at 35,000 feet. And it should still function even if you were floating in the intersteller void.
RE: need some basic circuit assistance - capacitor / transformer stuff
Z
RE: need some basic circuit assistance - capacitor / transformer stuff
anything practical !
A circuit is basically a loop , by normal convention power
arrives from the left ( but not always )
the diode allows half of the AC cycle to get through
to the capacitor and charge it up (More than 2000V)
A circuit is a simplified view of the real world ,
insulation may fail , isolated becomes connected !
and stray capacitances connect every conductive object,
more noticable at high voltage-or-frequency
RE: need some basic circuit assistance - capacitor / transformer stuff
Take a look at this http://www.davidbridgen.com/earth.htm
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