Voltage controlled attenuator or Voltage controlled amplifier,
Related post:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=47894
Related post:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=47894
Search the internet for 'light dependent resistors' or 'LDR'. This is a special kind of resistors whose value change depending on how much light intensity they are receiving
Also there are LDR + LED combos in a single package perfectly isolated from ambient light, they are sometimes used in the limiter sections of PA amplifiers, altough these parts are hard to find
The smartest feature of LDRs is that no electrical connection between the resistor part and the light-emitting part is required
Also there are LDR + LED combos in a single package perfectly isolated from ambient light, they are sometimes used in the limiter sections of PA amplifiers, altough these parts are hard to find
The smartest feature of LDRs is that no electrical connection between the resistor part and the light-emitting part is required
The LDR is a resistor the value of which can be controlled by the current through the LED inside. It is not difficult to convert a voltage to a varying current through an LED. I think it is a good suggestion.
We use Vactrol LDRs in guitar amps all the time. They serve as signal routing switches and as tremolo interfacecs.
Google Vactrol and you ought to find them easy enough.
Or make your own. Photoresistor and a light bulb wraped up in something light tight. Drive the bulb with your voltage and the resistance of hte photocell varies.
We use Vactrol LDRs in guitar amps all the time. They serve as signal routing switches and as tremolo interfacecs.
Google Vactrol and you ought to find them easy enough.
Or make your own. Photoresistor and a light bulb wraped up in something light tight. Drive the bulb with your voltage and the resistance of hte photocell varies.
Thanks for the ideas! I did find some info about optocouplers (same thing as the ldr + led I guess) previously, I'll look into it in more detail.
Here's a brief description of exactly what I'm trying to do.
I used to have a potentiometer that drove a gauge. But now I want to replace the potentiometer with a Hall effect rotary sensor (these have come down in price alot recently). The Hall effect sensor outputs a voltage.
The gauge is an industry standard gauge that is driven by a variable resistance. I cannot change the gauge.
The voltge to resistance conversions does need to be linear for a good reading on the gauge.
Thanks again for the ideas.
Here's a brief description of exactly what I'm trying to do.
I used to have a potentiometer that drove a gauge. But now I want to replace the potentiometer with a Hall effect rotary sensor (these have come down in price alot recently). The Hall effect sensor outputs a voltage.
The gauge is an industry standard gauge that is driven by a variable resistance. I cannot change the gauge.
The voltge to resistance conversions does need to be linear for a good reading on the gauge.
Thanks again for the ideas.
http://www.websters-online-dictionary.org/definition/gauge
What was this gauge for and what was the resistance controlling?
Why do I ask? Maybe you can use a voltage or a current to control?
you might check the display spec more closely, if it isn't poteniometric (voltage sensing) then it almost certainly responds to current drawn by the sense resistor from a fixed voltage, you could just put in(or sink) a voltage controlled current
a very few circuits might use a resistor to control an internal oscillator and use a frequency counter type display
i missed the part about this being about solid state audio amplifiers however
a very few circuits might use a resistor to control an internal oscillator and use a frequency counter type display
i missed the part about this being about solid state audio amplifiers however
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