Problem with full wave rectifier when function generator is used as input

we tried a full wave rectifier using a bridge circuit and we the circuit works well when i use a transformer as input but doesn't work when i use a function generator as input... why?

full wave rectifier

you should check the ratings of the instrument

try using an amplifier stage between the fn. gen. and the rectifier

full wave rectifier oscilloscope measurements

Hi,

There can be another problem: when you use a function gen, you may miss the isolation that the transformer gave you previously.
For instance you use a oscilloscope to check the full wave rectifier then the transformer isolates the earth/ground of the mains supply from the oscilloscpe earth/ground but in case of the function gen there is no such isolation: if you drive directly the diode bridge from the generator's output where one of the outputs is the earth/ground then it meets directly with the earth/ground of the oscilloscope, hence one diode in the bridge gets short-circuited the very moment you connect the oscilloscope (the two grounds/earths are met through the common mains' ground/earth).

If you use an earth/ground-independent instrument for measuring the full wave bridge output, then the above problem does not manifest of course.

unkarc

how to check generator rectifier

I'm agree with unkarc answear

try use a 1:1 transformer if you want use a Function Generator.

function generator full wave rectifier

A.Anand Srinivasan said:

we tried a full wave rectifier using a bridge circuit and we the circuit works well when i use a transformer as input but doesn't work when i use a function generator as input... why?

Click to expand...

Make sure the function generator has enough output current to drive the load.

Look at the function generator output with an oscilloscope to see if it has the expected voltage amplitude while it is connected to the full wave rectifier.

function of full wave rectifier circuit

hi
first you didnt mention the name of the dides you are using and the frequency of fn. ge. so cold you add them ....

regards

full wave rectifier functions

sorry... i forgot to mention abt the output... actually i got a halfwave rectified wave as output if i used a function generator... if it had been as unkarc said then the whole wave must have appeared... but here the signal was half-wave rectified.... so what is the possible answer

Added after 3 minutes:

as for the diode ... i used 1N1004(all four of them)...

full wave rectifier circuit

A.Anand Srinivasan said:

... actually i got a halfwave rectified wave as output if i used a function generator...

Click to expand...

First of all: set up the scope for a differential measurement and use two channels with two probes. Don't connect the probe grounds to any active circuitry or floating grounds. This will prevent the problem that unkarc pointed out and it may very well solve your problem.

If the problem still persists when you make a differential measurement, it would appear that the function generator output is attempting to drive into a low impedance load (e.g., short to ground through the bridge rectifiers) during half of its output cycle. To resolve this you must either:

1. Apply a DC level shift to the generator output.
2. Power the function generator through an isolation transformer.
3. Disconnect the load side of the bridge from the shared ground.

measuring a full wave rectifier

perhaps the function generator's output frequency is too high to be rectified,

or the function generator's drive ablity is too weak.

best regards

A.Anand Srinivasan said:

we tried a full wave rectifier using a bridge circuit and we the circuit works well when i use a transformer as input but doesn't work when i use a function generator as input... why?

Click to expand...