Motor Control Using 555 Timer
Motor Control Using 555 Timer
WATER LEVEL CONTROLLER
USING 555 TIMER
Department of TCE/ECE
JNNCE , Shimoga
Automatic Control of AC Motor
Thus Preventing overflow from
Over Head Tank.
OVER HEAD TANK
CIRCUIT BOARD BLOCK DIAGRAM:
Input From OHT
ABOUT THE 555 TIMER IC
• Introduced in 1972 by Hans Camenzind
at Signetics Corporation. Low cost , stable , low power.
• Manufactured 1 billion units / year .
• 8 pin mini DIP-8 pack.
• Includes 25 Transistors ,2 diodes and 15 resistors
in silicon chip.
• Used in timer , pulse generation and Oscillator applications .
1 – GND : Ground, low level (0 V)
2 – TRIGGER : Detects 1/3Vcc, Output high. Pin 2
controls over Pin 6.
3 - OUTPUT :This output is driven to approximately
1.7V below +V cc or GND
:A timing interval may be reset by driving
this input to GND
5 – CONTROL : Control access to the internal
voltage divider (by default, 2/3 VCC).
6 – THRESHOLD : The interval ends when the voltage at
THRESHOLD is greater than at CONTROL.
7 - DISCHARGE : Open collector output; may discharge
a capacitor between intervals.
: Positive supply voltage.( 3 to 15V)
Specifications of NE555:
1) Supply Voltage : 3 to 15 V
2) Supply Current : 3 to 15 mA
3) Output Current : 200mA (MaX)
4) Power Consumption : 225 mW @ 15V
Modes of Operation:
: Free Running mode, used as oscillator ,
provide time delay, adjust duty cycle.
2) Monostable : "one-shot" pulse generator.
Applications include timers,
bounce free switches.
: Basic flip-flop , Schmitt trigger.
555 ANALYSIS :
TRUTH TABLE : (SR FLIP FLOP)
WATER CONTROLLER TRUTH TABLE :
*When Water Below LOWER LEVEL :
Comparator 1 = high
Comparator 2 = Low
SR FLIP FLOP = SET (1) , Q bar ( OUTPUT ) = Low (DRIVES THE
*When Water Level Reaches UPPER LEVEL:
Comparator 1= Low
Comparator 2= High
SR FLIP FLOP = RESET (0) , Q bar (OUTPUT) =High ( RELAY OFF)
MOTOR SWITCHES “ON”
MOTOR SWITCHES “OFF”
RELAY : An Electromagnetic Switch
Relay Open :
Common - Normally
Relay Closed :
Common – Normally
LIST OF COMPONENTS REQUIRED:
1uF , 0.01uF
An Astable Circuit has no stable state - hence the name "astable".
The output continually switches state between high and low
without any intervention from the user, called a 'square' wave.
This type of circuit could be used to give a mechanism intermittent
motion by switching a motor on and off at regular intervals. It can
also be used to flash lamps and LEDs, and is useful as a 'clock' pulse
for other digital ICs and circuits.
A Monostable Circuit produces one pulse of a set length in
response to a trigger input such as a push button. The output of
the circuit stays in the low state until there is a trigger input, hence
the name "monostable" meaning "one stable state
A Bistable Mode or a Schmitt Trigger, has two stable states, high
and low. Taking the Trigger input low makes the output of the
circuit go into the high state. Taking the Reset input low makes the
output of the circuit go into the low state. A push button would be
placed at each end of the track so that when one is hit by the train,
it will either trigger or reset the bistable.