Home > Circuit Bricks > Voltage Clamp
UPDATED:.21:16 21 October 2013

  • Limits an input signal to a set voltage.
DC Voltage Clamp
  • The output will not rise above the voltage of the zener diode.
  • Maximum input voltage is around 18 volts. Increase R1 to 2.2K for input voltages over 20v.
  • The output will not have a very high current capability and should be buffered or fed to a high impedance input.

DC Voltage Clamp Circuit

AC Voltage Clamp
  • The zener diodes should be 0.7 volts less than the maximum required voltage - this is due to the forward voltage drop of diodes when forward biased.
  • So for 5v clamping, use 4.3 volt zener diodes.
AC Voltage Clamp Circuit

Written by Phil Townshend - 2008
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