Main Radar Home

 Radar theory Home

AP3302 Pt3 Contents

AP3302 Pt3 Section 2Contents

Contact the Editor

AP 3302 Pt. 3

Section 2


Clamping Circuits

In Fig. 7b before the input is applied, C charges to the bias voltage VB (in this example - 25V) and remains steady at this value. VR is zero and Vout = + VB = + 25V. Now let us consider the action from this point:

A to B. The input rises by 100V from zero. Since C cannot charge immediately Vc remains at - 25V and the voltage step of 100V is developed across R. Thus VR rises immediately to + 100V, and the diode cuts on. The output Vout rises to 100 + 25 = 125V.

B to C. With the diode conducting, C charges on a short time constant of CRD seconds and Vc rises quickly to + 75V as VR falls to zero. When VR reaches zero the output voltage Vout has fallen to + 25V. The diode is now cut off

C to D. The input falls by 100V to zero. Since Vc cannot change instantly both VR and Vout fall by 100V, VR to - 100V and Vc to - 75V. The diode remains cut off and Vc remains at + 75V. 


Previous page

To top of this page

Next Page

Constructed by Dick Barrett

(To e-mail me remove "ban_spam_" from my address)

ęCopyright 2000 - 2002 Dick Barrett

The right of Dick Barrett to be identified as author of this work has been asserted by him in accordance with the Copyright, Designs and Patents Act 1988.