AC signal divider

[neptune]

Hello people,
I want a device/Circuit which can make 2 AC signal source from one , with same amplitude and frequency. which can be used for two different circuits.
The problem i have encountered is that i cant make two independent AC signal out of one but merely deviding them on two different wires. if one signal encounters some load thn it will interfare with other siganl and even its mother signal.

 

[Ratchit]

nepture,

Use a transformer or two.

Ratch

 

[MrAl]

Hello people,
I want a device/Circuit which can make 2 AC signal source from one , with same amplitude and frequency. which can be used for two different circuits.
The problem i have encountered is that i cant make two independent AC signal out of one but merely deviding them on two different wires. if one signal encounters some load thn it will interfare with other siganl and even its mother signal.

Hi,

If it's just a signal, and the grounds are connected, sometimes you can just use a capacitor and series resistor and that provides enough isolation.

There's a trick you can use with AC but not with DC because AC doesnt need a directly connected ground...
If the grounds are not connected, sometimes you can use two sets of capacitors with series resistors, one set in the signal lead and the other in the ground lead. This isolated the signal and the ground lead too, but you have to be careful when connecting circuits that have very different ground potentials because a higher initial current surge can occur. With the resistor values chosen appropriately, you can minimize this problem.
If you want to you can also incorporate protections circuits consisting of zener diodes to protect against a current surge that could bother the main supply source.


You didnt say how much power you need to transfer so i assumed you were talking about signals only.

 

[carbonzit]

Two op-amps with a gain of 1 used as buffers? or even just a single op-amp with a low output impedance.

 

[neptune]

Hi,

If it's just a signal, and the grounds are connected, sometimes you can just use a capacitor and series resistor and that provides enough isolation.

There's a trick you can use with AC but not with DC because AC doesnt need a directly connected ground...
If the grounds are not connected, sometimes you can use two sets of capacitors with series resistors, one set in the signal lead and the other in the ground lead. This isolated the signal and the ground lead too, but you have to be careful when connecting circuits that have very different ground potentials because a higher initial current surge can occur. With the resistor values chosen appropriately, you can minimize this problem.
If you want to you can also incorporate protections circuits consisting of zener diodes to protect against a current surge that could bother the main supply source.


You didnt say how much power you need to transfer so i assumed you were talking about signals only.

I want to duplicate AC signal of 4V pk to pk power with 10 to 20 KHz of freq. from its mother signal
I didnt understand anything please post a schematic.

 

[neptune]

Two op-amps with a gain of 1 used as buffers? or even just a single op-amp with a low output impedance.

yes this seems to work well. but it is creating problem in further comparision. the two signals are not Exactly alike
1st one is orignal circuit and 2nd one is modified

 

[MrAl]

I want to duplicate AC signal of 4V pk to pk power with 10 to 20 KHz of freq. from its mother signal
I didnt understand anything please post a schematic.

Hi,

You didnt say what kind of problem you were having with the op amp(s).

Here's a drawing...

 

[neptune]

Excuse my naiveness, but i see 2 signal input and 4 output.
is there something i am missing

 

[MrAl]

Hi,

The lower lead of each output goes to load ground of the respective load, and the upper lead of each goes to load signal input.
You wanted to split the signal so you have one source and two loads.

 

[neptune]

pls check is this what you are talking about !

 

[alec_t]

No, something like the attached was intended. B and D are DC-isolated virtual grounds. I have simplified MrAl's circuit by removing two redundant resistors.

 

[MrAl]

pls check is this what you are talking about !

Hi again,


No not exactly...here's the correct drawing. Note that none of the resistors are redundant in the practical circuit unless you have special circumstances.

 

[neptune]

hey Mr. AI i have a question.
when i am changing value of resistor R5 and R6 , current going through them is same. (48uA AC) independent of R5 and R6 value
why is that ?
your circuit does a good job of shielding two signals from each other, i am going tp try it in my other circuts.

 

[MrAl]

Hi again,

If the load resistors R5 and R6 are not comparable to the series resistors in each section, it could appear that the AC current level does not change. Give different value series resistors it would change significantly if the capacitors were comparatively high in value too.

If you find you get too much loss you may end up using a buffer anyway. If not, you're good to go