Re: voltage controlled resistor

Franc Zabkar wrote:

On 17 May 2007 14:19:55 GMT, et472@xxxxxxxxxxxxxxxxxxx (Michael Black)
put finger to keyboard and composed:

Franc Zabkar (fzabkar@xxxxxxxxxxxxxxxxx) writes:
On 16 May 2007 10:43:47 -0700, cary.niza@xxxxxxxxx put finger to
keyboard and composed:

Does anyone know of an IC chip or discrete component intended to be
used as a variable resistor whose resistance value may be controlled
by varying its voltage input/signal

About 20 years ago I encountered a device consisting of a light source
(LED ?) and a light dependent resistor. IIRC the part came in a
package that was not much bigger than a TO92 transistor. I think
similar schemes are used to provide noiseless volume controls for
musical instruments, eg the expression pedals for pianos and organs.

And the poster hasn't really given enough detail.

Those things, and you could make them yourself if you had the light
dependent resistors, tend to be the simplest solution, because the
existing circuit only sees a variable resistor. I gather though
that they tended to be not so linear vs control voltage, and I don't
recall them coming in a wide range of values.

I would hazard a guess that these devices were mostly used in volume
control applications where the user provided the feedback. Hence
linearity may not have been a big issue.


There were incandescent versions for remote volume control
applications. Some Public Address amplifiers had sockets to add remote
volume controls.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida
.

Relevant Pages

  • Re: Any beefy coil driver chips?
    ... *PHUT* when the control voltage is sluggish, numerous resistors, and so ... Since I did the PWM SEPIC with one PIC and one power MOSFET, ... You need a resistor to ground otherwise... ...
    (sci.electronics.design)
  • Re: soundcard as oscilloscope
    ... >> I can control the amplitude of the wave form pretty easy by controlling ... >> either a variable resistor or the variac... ... I'm simply using a voltage divider(I've did it more complex at ...
    (sci.electronics.design)
  • Re: Gottlieb System 80 Power Supply Voltage dropping with CPU
    ... thanks for crediting Ed for the 5 ohm, 10 watt resistor idea; ... CR5 is your suggested replacement, ... I assume this is the correct orientation. ...
    (rec.games.pinball)
  • Re: voltage controlled resistor
    ... and a light dependent resistor. ... that they tended to be not so linear vs control voltage, ... Linearity in the control ... to get the varying resistance. ...
    (sci.electronics.components)
  • Re: Havent done anything real with OOP yet.
    ... >> temperature is measured. ... then Plant is more like what I assumed for Building and the Resistor ... I was using some traditional terms from control theory without ... the measured temperature goes out and the computed voltage comes in. ...
    (comp.object)