is-it normal for the brake pedal to sink a little bit when A/C engages?

[manteiv]

I have a Corolla 1996 DX, 1.6l, 5-speed

At a traffic light when I maintain my foot on the brake pedal, I notice it sinks a bit towards the floor whenever the A/C compressor engages, is-that a normal thing?

[kyoshiro]

maybe the brakebooster isnt producing enough pressure cuz of the extra electric pull from the compressor?