Sunday, January 3, 2010

Sound Card Oscilloscope Linux Simple Voltage Divider To Convert 5v To .5v For Sound Card Oscilloscope. What Values Do I Use ?

Simple Voltage Divider to convert 5v to .5v for sound card oscilloscope. What values do i use ? - sound card oscilloscope linux

I know it sounds simple. I want to test for normal or TTY + - 5V levels with my sound card and software called "sound card oscilloscope.

The cards are accepted his + / - .7 V, so that I would make a voltage divider for 1:10 of 5V. So I R1 and R2 = 100 ohms resistors 1kohm =. The only thing is that I still 4.80V .. R1 and R2

In still confused about what values I use with a voltage divider, for example, the ratio is anyway you can use 1 / 10 ohms or 1/10Kohm or 10/100kohm that are best for use in this case?

All recommended reading (link) would have taken too big, sorry i havent linear circuits, but only digital.

3 comments:

wingstwo said...

3 Problems:

1. Switch R1 and R2. You're back! Put considerable resistance between test points and +5 V.

2. Its formula is not correct. Here's the good:

R1 / (R1 + R2) = 100Ω/110Ω = 0.91

Voltage = 0.91 ∙ 5V = 4.55V

Since yours is a bit high, perhaps the values of R are a small, perhaps multimeter error, power is perhaps a little high. O audio input can be measured power.

3. That is not good for most CMOS and TTL circuits. It will look much current to 50 mA at 5 V difference and 100Ω.

I want to go much higher resistance, between 1 and 10 million for large, 1 / 9, for the resistance of others. If you want to use a very close relationship, the less the resistance of a value, take a little lower in series with a much smaller boat to a very precise value. Adjust until you have exactly 0.5V.

Higher resistance will take longer to fix up, and shaken the value of more fees. If the sound card CMOS, high-strength should be good. Examine ways is to compare the resultsmore resistance against another group, the 1 / 2 or less. You get the same answer, it must be good to go. The speed is so slow that the settlement should be time no problem.

Edit: Ron is right that a continuous assessment should be done (but almost never is). The instruments tend to use high impedance CMOS input circuit test significant burden to be avoided. If the resistance is up, supplies the range of input impedance of the sound card, or the current drawn by changing the sound card in the results. Maybe you would like the range of 100K or 1M vice versa. In any case, check to check.

When you add a diode, the wave is totally changed. Little or no signals will be blocked, and only the tops of the highest voltage was recorded. Not recommended.

yaktur said...

You can use a voltage divider ..... or why not just remove the excess "of" tension with a Z-4.7V in series with the signal? You can not find a 4.5-volt-Z, but it works maybe 4.7?

Mouser tests as a diode, MM3Z4V7C

http://ca.mouser.com/Search/ProductDetai ...

yaktur said...

You can use a voltage divider ..... or why not just remove the excess "of" tension with a Z-4.7V in series with the signal? You can not find a 4.5-volt-Z, but it works maybe 4.7?

Mouser tests as a diode, MM3Z4V7C

http://ca.mouser.com/Search/ProductDetai ...

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