Why Transistor's are used after CT for rectification instead of Bridge rectifier.

[SyedFahad]

Hi, We have made a circuit to measure current. As we need this current to monitor through PIC.

Here my question is that we have used CT , which takes current at input and generates voltage proportional to it at the output. After it we have used Two Transistors instead of Bridge rectifier. Why these Transistors are used here instead of simple bridge rectifier for current measuring circuit (Current Sensor) for PIC.

 

[barry]

It's YOUR circuit; why don't YOU tell US why you used transistors???? Did you copy this from somewhere? Do you, perhaps, have a schematic? And that looks a voltage transformer, not a current transformer (although they are essentially the same).

 

[SyedFahad]

Hi, actually we have given this task to measure current through PIC. The circuit was also given to us. We have implemented and its working. But i am curious to know that why Transistors are used instead of Bridge rectifier. I am unable to get answer ....

 

[godfreyl]

If you show a circuit diagram, someone may be able to help.

 

[ahsan_i_h]

Post the transistor part numbers.
Try to make a rough sketch about how the transistors and other components are connected, then post it. (at least post the picture of bottom side.)

 

[schmitt trigger]

I guess that what they are doing is using the emitter-base and collector-base junctions as a dual diode- i.e. one leg of a rectifier bridge.

But without a schematic...that is only a GUESS.

 

[D.A.(Tony)Stewart]

We are not mind readers, but my crystal ball says that somehow the transistor may trigger at the same diode drop but then provides a bigger burden to the CT transformer with the Cap and external bias.

A good answer always follows the best question where all the relevant info is provided.

 

[goldsmith]

Hi, We have made a circuit to measure current. As we need this current to monitor through PIC.

Here my question is that we have used CT , which takes current at input and generates voltage proportional to it at the output. After it we have used Two Transistors instead of Bridge rectifier. Why these Transistors are used here instead of simple bridge rectifier for current measuring circuit (Current Sensor) for PIC.img_20140716_163825-1.jpg

Hi SyedFahad
I guess i should send a ghost to see behind of your board and part numbers and your schematic ! ha ha !
Besides the kidding , when you want ask something , thing think about this issue that , nobody knows what you're up to do so explain exactly . nobody can't be oracle , so send the schematic . then be sure , everybody in here will try to help as well and you'll get your answer sooner .
Best Wishes
Goldsmith

 

[ahsan_i_h]

Hi, actually we have given this task to measure current through PIC. The circuit was also given to us. We have implemented and its working. But i am curious to know that why Transistors are used instead of Bridge rectifier. I am unable to get answer ....

Are you sure they are transistors ?
I guess they are dual diodes in a TO-92 package (e.g. MSD6100(common cathode) and MSD6150(common anode)) and formed the bridge rectifier.

datasheet links:

http://pdf.datasheetcatalog.com/datasheet/on_semiconductor/MSD6100-D.PDF
http://pdf.datasheetcatalog.com/datasheet/on_semiconductor/MSD6150-D.PDF

 

[schmitt trigger]

The original poster has gone AWOL