pulse response of a battery on CRO.

[palash722]

Hey Guys...

I have a question... is it possible to give a square wave, 5v P-P, 20khz pulse to the 12v, automobile battery with internal resistance of a battery interms of 300m_ohms...??? and see the response of the same on the CRO interms of the pulse...??? I've tried to create a scematic for the same... just let me know if any modification is required or if any other schematic you can think of... just see the zipped file...

thanks a ton guys...

Darshan

 

[audioguru]

A car battery can supply abour 200A with a voltage drop of 3V. so its internal resistance is 3V/200A= 15mV.
Since the internal resistance of your car battery is 20 times higher then it must be nearly dead.

I don't know why you are trying to feed a 1.7V pulse from the output of an LM317 into the input of a 12V battery that is not connected to ground in the circuit. The max output high voltage of a 555 with a 5V supply is 3.7V. The max output of an LM317 with a 3.7V input is 1.7V.

 

[palash722]

yes my friend you are right... actually my whole and soul aim is to give a pulse to the battery and get the response of it (while discharging) on the CRO... I got the LM 317 circuit on wikipedia where if I feed 5v input, I can get 3.5 V output with 1Amp... and I thought that if I want to generate a pulse, I can generate it with 555timer and can give the output of the same to LM 317...!!

if I am wrong, can you suggest me any way I can successfully do the experiment...??? do I need to do any modifications in my current cke or you do have anything else in your mind...??

I would really appriciate your help...

Regards,
Darshan

 

[palash722]

regd. the internal resistance, I've charged the battery so it is like 16mV.

 

[Roff]

I still don't understand what you are trying to do.

 

[audioguru]

A fully charged car battery is 13.8V. Your circuit has an output of about 1.8V.
The output current of an LM317 is the same as its input current.

You have the LM317 used and connected backwards. It is supposed to supply about 1.8V with 1A of current to a load, not discharge current from a higher voltage battery.

You need a power transistor or Mosfet to provide a discharge path to ground, like this:

 

[palash722]

thank you so much... let me try with this and we'll get back to you with the response....!!