Double Clipper/ Limiter circuit.

suppose you have a sine wave of 5volts. peak voltage. i.e (10v p-p)
like shown below. 

The popular question is..  Design a circuit which clips the sine wave at 2v(Say) in the positive direction and at -3v in the negative direction. I.e cut the wave form at 2volts and at -3v.

Solution : 

Yes you need diode and voltage supplies to do that. 

1)During positive half cycle of the input  

• when vin<2v,Both D7 and D8 are reverse biased.So output follows input  
• when vin>2v. D7 is forward biased and D8 is reverse biased.

D7 forward voltage is 0.7v.

So output is 0.7+1.3=2v.

2) During negative half cycle of the input.

• when Vin>-3v(i.e -1,-2) Both D7 and D8 are reverse biased and output follows input

• when vin< -3v,  D8 is forward biased. 

So finally we get a wave which is clipped at 2v and at -3v

This is the popular double limiter circuit. which will be asked in many competitive exams.Check the circuit in your analog labs. CHEERS!