Differentiator

Aim: -

To design and simulate a Differentiator circuit.

Components: -

Name	EDWin Components Used	Description	Number of components required
RES	RC05	Resistor	1
CAP	CASE-A600	Capacitor	1
VGEN	SMB_VGEN	Ac voltage source	1
GND	SMB_SPL0	Ground	1

Theory: -

A circuit in which output voltage is directly proportional to the derivative of input is known as a differentiating circuit. A differentiating circuit is a simple RC series circuit with output taken across the resistor R.

In order to achieve good differentiation, the following conditions should be satisfied:

The time constant RC of the circuit should be smaller than the time period of the input wave.
The value of Xc should be 10 or more times larger than R at operating frequency.

Let e_ibe the input alternating voltage and i be the resulting alternating current. The charge q on the capacitor at any instant is

e_c

C e_c

e_c

Since capacitive reactance is very much larger than R, the input voltage can be considered to be equal to the capacitor voltage with negligible error. i.e. e_{c =} e_i

e_i

Output Voltage, e_{o =}iR

e_i e_i

(input)

Hence the output is proportional to the time derivative of the input.

Procedure: -

EDWin 2000 -> Schematic Editor: The circuit diagram is drawn by loading components from the library. Wiring and proper net assignment has been made.

The values are assigned for relevant components.

EDWin 2000 -> Mixed Mode Simulator: The circuit is preprocessed. The test points and waveform markers are placed in input and output of the circuit. GND net is set as reference net. The Transient Analysis parameters have been set. The Transient Analysis is executed and output waveform is observed in Waveform Viewer.

Result: -

The output waveform may be observed in the waveform viewer.