# ±10 V quick question

Discussion in 'General Electronics Chat' started by Tony Elliott, Feb 10, 2016.

1. ### Tony Elliott Thread Starter Member

May 8, 2015
140
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±10 V

Does this mean 0 to +10 volts or -10 to +10 volts?

2. ### Lestraveled Well-Known Member

May 19, 2014
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±10 V can mean a -10 to +10 range. More often it means a dual power supply, -10V and +10V.

3. ### paulktreg Distinguished Member

Jun 2, 2008
622
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Depends on context?

If something was written 100±10 V then it would indicate an allowable voltage range of 90V to 110V.

4. ### cmartinez AAC Fanatic!

Jan 17, 2007
3,698
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It could also be the excitation range of some devices, like load cells, for instance. But as Paul just said, more context is needed.

Jul 18, 2013
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±10 V
Also used for bi directional analogue servo drive command.
Max.

6. ### Tony Elliott Thread Starter Member

May 8, 2015
140
2
It is based on this text.
LFO out is ± 5V

Its to do with attenuating a sine wave.

7. ### cmartinez AAC Fanatic!

Jan 17, 2007
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It would really help if you posted the whole document

8. ### Brevor Active Member

Apr 9, 2011
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I would take that as meaning the Low frequency Oscillator swings between +5 and-5 Volts.

9. ### Tony Elliott Thread Starter Member

May 8, 2015
140
2
Here is the instructions, the bit is on the left hand top corner. Its creating a panning circuit using Voltage Controlled Amplifiers. I also need to work out how to how to make a wave 180 degrees out of phase.

10. ### AnalogKid Distinguished Member

Aug 1, 2013
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Based on that, the LFO output is a 10 V peak-to peak sinewve centered about GND. Thus the two peaks are +5V and -5V with respect to GND. The required signal is 0V to 5 V, so that is a 2:1 attenuation. The required output centerpoint is +2.5V, so that is a 2.5V addition or offset. So the total conversion circuit is a gain of 0.5 and an offset of +2.5V.

The two circuits on the left indicate creating the offset by combining a DC voltage with the LFO signal. Another approach is to bias the input to the amplifier at 2.5V and AC couple the LFO signal. This prevents any residual DC in the LFO signal from winding up in the output.

Why are you amplitude-modulating audio with a low frequency sinewave?

ak

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11. ### Lestraveled Well-Known Member

May 19, 2014
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The two op-amp circuits do that for you. One is inverting and the other is non-inverting.

Like AK said, you need a 2.5 Volt reference and work out the resistor values for a gain of .5

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12. ### Tony Elliott Thread Starter Member

May 8, 2015
140
2
I am creating a voltage controlled panning circuit to experiment with space.

13. ### Lestraveled Well-Known Member

May 19, 2014
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Have you been tasked to build this circuit and to work out the details? Is so, do you know how to determine the resistor values for the op-amps?

14. ### #12 Expert

Nov 30, 2010
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I can visualize the result. A stereo signal would seem to move back and forth across the room as one speaker goes from full output to zero and back, while the other speaker goes from zero output to full and back to zero. Bit of a mind-melt, but sometimes that's what you want to do with the art.

For those to whom this is not obvious, I hope I explained it.
In addition, I recommend people withhold judgement about the motives. We do lots of circuits here without deciding if the Thread Poster has good reasons to do them.

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15. ### Tony Elliott Thread Starter Member

May 8, 2015
140
2
The resistor values are already calculated, this is the VCA I need to use parts of this schematic.

16. ### Lestraveled Well-Known Member

May 19, 2014
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@#12
Sounds like a stereo tremolo, but bigger.

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17. ### #12 Expert

Nov 30, 2010
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You would have to turn one channel off to reduce this to merely a Tremolo!

18. ### Lestraveled Well-Known Member

May 19, 2014
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Yup........bigger......Tremolo on steroids

Maybe the TS should go for a 4 channel panning thingamajig. Remember you can add "middle" channels also.

19. ### #12 Expert

Nov 30, 2010
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That would be so much fun!

20. ### AnalogKid Distinguished Member

Aug 1, 2013
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I know this part. It is a classic from audio console designs in the 80's. Getting the control voltage just right usually takes a couple of trimpots, but it will do what you want. Any other questions?

ak