Babar,

1.
A typical power supply:
transformer
bridge rectifier
cap 1000µF
ceramic 100nF
voltage regulator e.g. 8705
ceramic 100nF
cap 100µF
suppressor diode e.g. P6KE6V8
ceramic 100nF
micro (89C2051)

The ceramics must be close
to the 7805 and the 89C2051.
This was good for up to 1Amp.

2.
On using a triac, there is the
better way to control it digital:
You insert a diode after the bridge
and before the 1000µF. So the voltage
before this diode goes through zero
following the AC input. Over ~10kOhm
connect a transistor basis (emitter to ground and collector to an interrupt
input).
So you get a transition interrupt
on every AC voltage rising.
The interrupt start a timer with the desired counting value, and
on the timer overflow interrupt,
give a short on pulse to the triac.
At 50Hz AC input the delay time can
be 0 to 10msec (50Hz AC give
100 half waves of 10msec).
0msec stands for maximum on time
(max power) and 10msec for motor off.

So the motor speed depends only
from the delay time and the AC input
frequency.

E.g. at 12MHz the timer must be load with a value between -1 (= max speed)
and -10000 (= 10msec delay = off).


Peter