• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Differentiator

Status
Not open for further replies.

jinanok

New Member
Hi,

i was trying to differentiate a 3Mhz square wave of 15V peak ,,
i used one 10pF ceramic capacitor and one 1K resistor , i m getting the differentiated wave form but the ouput peek is reducing to 1V ,,

how i will get 15V peek differentated wave form ,,, why the voltage peek is reducing ????????/


please help me to solve this problem.................
 

ericgibbs

Well-Known Member
Most Helpful Member
Hi,

i was trying to differentiate a 3Mhz square wave of 15V peak ,,
i used one 10pF ceramic capacitor and one 1K resistor , i m getting the differentiated wave form but the ouput peek is reducing to 1V ,,

how i will get 15V peek differentated wave form ,,, why the voltage peek is reducing ????????/


please help me to solve this problem.................
hi,:)

What 'resistance' is the output of the 'diff' seeing, ie: the load impedance.?

also whats driving the 'diff'.?

EDIT: how are you measuring the diff output pulse, eg: scope with probe, resistance/cap of probe/scope.?
 
Last edited:

jinanok

New Member
the differentiator input is comg from a driver is (EL 7182) and output i m conecting to a CRO ,, latter i have to connect this signal to a 2n2222 for switching ...
 

ericgibbs

Well-Known Member
Most Helpful Member
the differentiator input is comg from a driver is (EL 7182) and output i m conecting to a CRO ,, latter i have to connect this signal to a 2n2222 for switching ...
hi,
If the capacitance of the cro and probe are high the diff signal will be attenuated.

Also if using a *10 probe, check the cap trim.!

Are you using a series resistor from the output of the diff to the base of the 2N2222.?


EDIT: simulations indicate the 2N2222 is not fast enough to give a sharp output pulse.
 
Last edited:

crutschow

Well-Known Member
Most Helpful Member
With a 10pF differentiating capacitor, just about any stray circuit capacitance is greater than that and will reduce the signal amplitude accordingly. Even a 10:1 probe will have close to 10pF of capacitance. Try using a larger capacitor.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top