Loading effect

Discussion in 'General Electronics Chat' started by yifei87, Oct 29, 2008.

  1. yifei87

    Thread Starter Member

    Sep 7, 2008
    hey, guy

    What is loading effect and how exactly it function or affect on?
    why a capacitor will lead to loading effect?
  2. mik3

    Senior Member

    Feb 4, 2008
    Everything which draws current can cause a loading effect not only capacitors.
    If you construct, say a low pass filter by using a capacitor and a resistor, and you calculate the cut-off frequency to be say 100Hz and then connect a load on the output of the filter the cut-off frequency will change. This is called loading and in this case it affects the cut-off frequency, in other cases it may affect other values.
  3. StephenDJ

    Active Member

    May 31, 2008
    Loading has to do with the fact that the load (device to be driven) is effectively connected in parallel with the rest of output circuit which is attempting maintain the output voltage. But because of the parallel connection, the overall opposition to current decreases thus requiring more current to flow from the output - current that the output may or may not be able to provide. If it does not provide, the output's voltage will fall.
    Last edited: Oct 30, 2008
  4. KL7AJ

    Senior Member

    Nov 4, 2008
    Indeed. Undesirable loading effects can occur in countless applications, from DC to Daylight. For DC circuits, it's important to have a very high resistance voltmeter...this is why the VTVM was invented (vacuum tube voltemeter)...back in the dark ages

    For high frequency "R.F." circuits, an oscilloscope probe can cause circuit loading because of the probe capacitance....which is why it's important to use a 10:1 divider probe for rf work. The divider probe drops the voltage by a factor of 10, but reduces capacitive loading by the same amount.