my oscilloscpe seems to show one half wave

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1

I made this full wave rectifier on my breadboard.All the 4 leds are lite up working.

I have a resister and cap on the output.When I hook up my oscilloscope it shows one

half wave.When I flip the leads I get one half wave upside down.

Don’t know why I don’t get full wave. It seems to be hooked up right. The ohms resister

is 220 and 1000 uf cap.

2

Don’t know why I don’t get full wave.

You probably wired it incorrectly.

3

It’s such a simple circuit I don’t think that would be possible. Thanks for the input.There are 2 onehalf waves

in the bridge type full wave circuit. there must be another reason.

4

What are you powering the bridge from? Can you post a schematic and show where you connect the scope?

Which leads are you flipping?

/mike

5

http://i168.photobucket.com/albums/u181 … sort=3&o=1

I hook the oscilloscope accrossed the resistor

6

I get

Sorry, the requested page does not exist.

for the link

7

Fixed the link for you: (actually, if I point at it Google Chrome did it for me)

http://s168.photobucket.com/user/john75 … sort=3&o=1

Make a picture of the actual board too. With clearly visible parts orientation. Showing the intended schematic is one thing. But the actual setup contains the error that we need to find!

And is this the link where you got your example from? http://www.electronics-tutorials.ws/diode/diode_6.html

You never mentioned any transformer coils. If they are part of your circuit, could one side of them be connected in reverse?

8

I’m confused when you say “the 4 leds are lite up working”.

You’re not using the LEDs as diodes for the bridge, are you?

This thread

https://www.quora.com/Can-an-LED-be-use … are-diodes

says:

it behaves in a diode fashion blocking current in one direction and not in the other.

But beware, in several respects (e.g. specifications or electrical characteristics) its a poor diode.

The reverse breakdown voltage is much lower than normal diodes, you might see breakdown at 15 or 20 volts or even less. Also the reverse leakage is much higher,

The safe forward current is limited, to the diode continuous operating currents around 10, 20, 30 mA and it will light up. This might be OK for small signal applications but not power rectifiers which can be 10’s of amps.

And the forward voltage drop is quite a bit larger, usually 2 V or up to 3V instead of 0.7. Making a much less than ideal diode.

9

Also, when you say:

normanjohnson:
When I hook up my oscilloscope it shows one

half wave.

do you mean that you see one half of the full AC wave and then a gap and then repeat?

or do you mean you see one half butted up against one half and then repeat (which would be expected).

could be if you’re using the LEDs for the bridge diodes that you burnt out one of them.