Discussion in 'General Electronics Chat' started by vaneet, Jan 25, 2006.

  1. vaneet

    Thread Starter New Member

    Jan 25, 2006
    Hello all! I am very new in eelctronic circuit design. I am struck with some problem related with clamping. I have got one sensor which gives frequency pulse output of around 5 kHZ and voltage level of this pulse is between 3.5 Volts to 11.3 volts.

    I want to clamp the lower value of this voltage which is 3.5 volts to zero volts. SO, i want pulse signal of same frequency as I/P signal but the voltage level should be between 0 Volts to 7.8 Volts .
    can anybody among this team of technocrats help me out in this???
  2. Gadget

    Distinguished Member

    Jan 10, 2006
    Lot of things we don't know, i.e. circuit impeadence (input, output) etc. Many different methods may be applicable, using a buffer may be the best.... another simple method may just be to use a 3.3v zener (or as close to 3.5 as u can find) in series with the signal with a pull down resistor of suitable value on the output.
  3. aac

    Active Member

    Jun 13, 2005
    What you need ia a DC restorer circuit. A simple approach is a capacitor into a diode connected to ground. What happens in a DC restorer is that over many cycles of your sensor output the capacitor charges up to the average value of your signal. This shifts the signal down by that amount after the capacitor. Of course how much the signal is shifted depends on the duty cycle, source resistance, and load resistance of your circuit.