Voltage Range Limiting

Discussion in 'The Projects Forum' started by kchrisc, Jan 12, 2013.

  1. kchrisc

    Thread Starter New Member

    Jan 12, 2013
    2
    0
    Is there a way to control a voltage in a circuit so that it only passes to another part of the circuit a certain voltage range? Voltages below the low-end of the range and above the high-end are blocked?

    I.e. a circuit that can use a 4V to 5V (these voltages are just examples) source but ignore anything below or above those voltages.

    I've thought of JFETs and diodes to create a high-end or low-end but can't seem to workout what to use to create a usable range only.
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,440
    3,361
    Sure. you can use zener diodes.
     
  3. BillB3857

    Senior Member

    Feb 28, 2009
    2,400
    348
    Easiest way would be to have voltage rails of 4.3 and 4.7 available. Like this......Or like MrChips says, use zeners.
     
  4. kchrisc

    Thread Starter New Member

    Jan 12, 2013
    2
    0
    Thanks for the replies however I need to constrain voltage to between a range. If the voltage supplied to this part of the circuit is below a certain point it is ignored and if it is above a certain voltage it is also ignored. I haven't had much luck in figuring this out on my own.
    4v
    |
    |
    ---->4V
    |
    |
    Pass 4 volts

    4.5v
    |
    |
    ---->4.5V
    |
    |
    Pass 4.5 volts

    5v
    |
    |
    ----X0V
    |
    |
    No pass 5 volts

    Thank you.
     
    Last edited: Jan 13, 2013
  5. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
    6,357
    718
    Did you see the solution in BillB3857's post? You only need to change the upper and lower voltages to change the range. Look at the output waveforms in the sim, yellow is output, green is input.
     
  6. crutschow

    Expert

    Mar 14, 2008
    13,009
    3,233
    Do you need to have the voltage disconnected if it's above or below the limit? If so you could use a window comparator controlling a MOSFET switch.
     
Loading...