# [SOLVED] Biasing an AC signal

#### Track99

Joined Jun 30, 2022
57
Imagine a AC signal whose function is Sin(x).
We mess around with the circuit and see a new function on our scope.
The new function of the AC signal is now Sin(x)+5.
This is called DC bias.

Imagine a AC signal whose function is Sin(x).
We mess around with the circuit and see a new function on our scope.
The new function of the AC signal is now Sin(x+5).
This is called ______ bias?

What kinda bias is in the second scenario? Is it called Phase bias? ( I am guessing Phase Bias cause the graph of Sin(x+5) moved right by about Pi/3 radians.
Ty

#### WBahn

Joined Mar 31, 2012
29,510
What is the signal x?

I suppose you could call the second case a phase bias.

Where do you come up with pi/3?

Assuming x is a function of time, such as wt for simplicity, then adding 5 radians to the phase would shift the trace 5 radians to the left.

#### Track99

Joined Jun 30, 2022
57
What is the signal x?

I suppose you could call the second case a phase bias.

Where do you come up with pi/3?

Assuming x is a function of time, such as wt for simplicity, then adding 5 radians to the phase would shift the trace 5 radians to the left.

Phase Bias? Ok, I guess that answers my question. Question has been answered. Ty

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#### MrChips

Joined Oct 2, 2009
29,848
The generic formula is
y = sin(x) where x is angle in radians.

If this is an AC signal, one could write it as
v = Asin(2πft) where t = time, f = frequency
or,
v = Asin(2πft + θ)
where θ would be called phase shift.