circuit explanation

can sum1 plz help me with this circuit diagram..I m planning to construct a frequency synthesizer circuit and i found this circuit diagram..but i m unable to figure out a component..can any1 explain 2me what is the part with the VDD from pin 9,Vss from pin 8 and pin 12 connected to the phase comparator 2, plz help me..

hi liverpool_fan
i not understand correctly
ru confused in power supply
Vdd and Vss

hey majoka...im jz confused as to what component is dat?is dat a power supply?cz it has pin numbers so i m a bit confused..

It is a simple 'D' type data latch with SET and RESET.
If you search through enough CMOS data sheets you can probably identify which one.

@ liverpool_fan
that is a D flip flop with set and reset pin
D=vdd
it is an input bit
R=reset
S=set
Q=state 1
Q'=state2
Q and Q' are outputs it inverted output to each other
if Q=1 then Q' is zero and vice-versa
in TTL it may be a 74LS74
in CMOS it may be a CD4013

thankz majoka!thankz a lot!
neway i have another question for u..below is an IR transmitter and receiver circuit..can u tell whether the 20k resistor is connected to pin number 3 or not?

and another tin...after constructing this circuit i tried testing it..bt even when there is an obstacle near the IR transmitter..it is not blinking...and the normal LED which is supposed to blink only when the IR sensor have detected an object,is lighted..is the IR transmitter supposed to blink or emit any light when an object is detected?plz help me

@liverpool_fan

can u tell whether the 20k resistor is connected to pin number 3 or not?

20k used is a variable resistor it has 3 terminals here it is used as voltage divider as reference to all non inverting terminals, yes it is definitely connected connect it to center terminal of variable resistor .

and another tin...after constructing this circuit i tried testing it..bt even when there is an obstacle near the IR transmitter..it is not blinking...and the normal LED which is supposed to blink only when the IR sensor have detected an object,is lighted..is the IR transmitter supposed to blink or emit any light when an object is detected?plz help me

here neither IR led nor output led blinks, IR led just glows like any other led,
when photo diode senses the the IR light from IR led the output LED will be OFF
when photo diode does not receive any IR light the output LED will be ON

hey jeswanthmg..thankz a lot for the explanation..so let me confirm again..I shud connect all the pins(3,5,10,12)all to the center terminal of the variable resistor rite?n the other 2 terminals will each b connected to ground and to the power supply rite?
thankz again!

Yeah thats right enjoy