555 TIMER THE MOST VERSATILE IC USED IN ELECTRONICS CIRCUITS ELECTROKRITI V6.0 INNOVATE TO IMPLEMENT… TEAM EHC
555 TIMER
THE MOST VERSATILE IC
USED IN ELECTRONICS
CIRCUITSELECTROKRITI V6.0INNOVATE TO IMPLEMENT…TEAM EHC
WHAT IS 555 TIMER
IT IS A 8 PIN IC.
GENERALLY USED TO GENERATE
CLOCK
PULSE OF WIDE RANGE OF
FREQUENCY
CAN BE ALSO USED TO
GENERATE SPECIFIC TIME DELAYTEAM EHC
INSIDE 555 TIMER
-
+-
+
RESET
SET
Q
Q
COMP1
COMP2
Flip-Flop
3 RESISTORS OF 5K
2 COMPARATORS
S-R FLIP FLOP
TRANSISTOR
TEAM EHC
COMPARATOR
-
+
V1
V2
VOUT
IF V1>V2 THEN VOUT = -
VSAT
IF V1<V2 THEN VOUT =
+VSAT
+VSA
T
-VSAT
-
+-
+
RESET
SET
Q
Q
COMP1
COMP2
Flip-Flop
TEAM EHC
3 RESISTORS VCC
0.66 VCC
0.33 VCC
USED AS VOLTAGE DIVIDER NETWORK
GIVES THE REFERENCE VOLTAGE TO THE COMPARATORS
-
+-
+
RESET
SET
Q
Q
COMP1
COMP2
Flip-Flop
TEAM EHC
S-R FLIP FLOP
RESET
SET Q
Flip-Flop
Q
S R Q Q’0 0 HOL
D
1 0 1 0
0 1 0 1
-
+-
+
RESET
SET
Q
Q
COMP1
COMP2
Flip-Flop
TEAM EHC
TRANSISTORA
B
VI
N
C
E
VI
N
USED AS A SWITCH
IF VIN=1 THEN C-E IS SHORTED
IF VIN=0 THEN C-E IS OPEN
CKT
-
+-
+
RESET
SET
Q
Q
COMP1
COMP2
Flip-Flop
TEAM EHC
PIN CONFIGURATION
Control Voltage (5)
Threshold Voltage (6)
Trigger Voltage (2)
Ground (1)
Vcc (8) Discharge (7)
Reset (4)
Output (3)
-
+
-
+
RESET
SET
Q
Q
COMP1
COMP2
Flip-Flop
TEAM EHC
MODE OF OPERATION
MONOSTABLE MODE
ASTABLE MODE
TEAM EHC
ASTABLE MODE
TEAM EHC
8
5
6
2
1 4
3
7
ASTABLE MODE CALCULATION
TIME PERIOD TON=0.693(RA+RB)C TOFF=0.693RBC TTOT=0.693(RA+2RB)C
CAN YOU CALCULATE THE FREQUENCY AND DUTY CYCLE OF THE ASTABLE MODE ?
TEAM EHC
MONOSTABLE CALCULATION
T = 1.1RC
TEAM EHC
MONOSTABLE MODE
TEAM EHC
8
5
6
2
1 4
3
7
LETS MAKE IT
TEAM EHC