RLC clipper circuit

Discussion in 'Homework Help' started by eceeng, Jul 2, 2007.

  1. eceeng

    Thread Starter Member

    May 8, 2007
    Is it possible to design a clipper circuit by just using inductors, capacitors and resistors? We are challenged to design a clipper circuit without the use of diodes.

    hope to hear from you guys soon.

    thanks a lot...
  2. thingmaker3

    Retired Moderator

    May 16, 2005
    Your instructor is having fun at your expense. Clippers require active components such as diodes, transistors, triodes, whatever. The active device must be non-linear. Capacitors, resistors, and inductors are linear.
  3. spar59

    Active Member

    Aug 4, 2007
    Actually technically an inductor is only linear unless the core saturates, if this does occur the inductive reactance disappears and you are left with its d.c. resistance only.

    This phenomenon was used in 1960s /70s battery chargers in the form of transductors - two double wound inductors (or transformers if you prefer) the primaries were wired in series between the mains and the rectifier transformer and the secondaries were wound in series but anti-phase so no output voltage. With nothing connected to the secondaries they behaved as inductors - high impedance hence little input to the charger transformer. However apply a d.c. control voltage to the secondary and the cores begin to progressively saturate - inductance drops - current increases - batteries get charged.

    From your point of view though if you create a series circuit or resistor and inductor and apply volts across them and pick an output from across the inductor as you increase the input voltage you will find that eventually the inductor core saturates and the voltage won't increase linearly anymore.

    If you can get hold of a current transformer and apply volts to its output winding and measure current - all is linear until it starts to saturate then current rapidly shoots up. In this case you can find what is called the knee point which is when a 10% increase in voltage gives a 50% increase in current - this is done during commissioning tests to ensure that it will be being used on the linear part of its characteristic (good practice would never use a current transformer more than half way towards to the knee point), as a matter of interest they are also non-linear at very low excitation - the ankle point.