Showing posts with label timer. Show all posts
Showing posts with label timer. Show all posts
Wednesday, April 10, 2013
BURGLAR ALARM USING IC TIMER 555 556 ELECTRONIC DIAGRAM
BURGLAR ALARM USING IC TIMER 555/556 ELECTRONIC DIAGRAM
circuit diagram of burglar alarm using IC timer 555/556 is functioned as an alarm to prevent thief entering your house. The alarm would produce loud sound when a thin wire connecting resistor R1 with IC pin no 4 is broken. Thin fiber is used as the wire. The thinner the wire, the more responsive the alarm. This circuit needs 5-15V power supply, buzzer is used as a speaker. Here is the circuit schematic :
Parts list :
- Resistor R1 : 10k
- Resistor R2 : 68k
- Resistor R3 : 1k
- Polar capacitor C1 : 1uF/15 B
- Capacitor C2-C3 : 0.01uF
- IC Timer : NE555
Monday, April 8, 2013
LED Flasher Circuit Using 555 Timer IC
This is a simple LED flasher project that uses a common 555 timer IC for its operation. It is configured as an astable mode which means that its output is a square wave oscillator. Two LEDs are connected to its output in such a way that when one LED is ON, the other LED will turn OFF.
It uses only 10 simple parts that are easily available at any electronic shops. Capacitor C2 charges exponentially through resistors R1, R2 and the resistance of the trimpot. When C2 has charged to about 2/3 VCC it stops charging and it discharges to about 1/3 VCC through R2 and the trimpot resistance via pin 7. This is the standard operation of a 555 timer. When a Vcc of 5 V to 15 V DC is applied to the circuit, the LED will start to flash.
The frequency of the flashing can be changed by varying the resistance of the potentiometer or trimpot.Parts List The parts list of the simple LED project is as shown below.
Thursday, April 4, 2013
How to Make a Long Duration Timer Circuit
A timer in electronics is essentially a device which is used for producing time delay intervals for switching a connected load. The time delay is set externally by the user as per the requirement.
A simple timer can be built through many countless options. You can transistors, CMOS gates like NAND gates, NOT gates, linear ICs like 555, 741, 324, or simply more specific type of CMOS IC like the 4060.
All these devices besically generate oscillations which are adjustable right from a few Hz a second to a atomic fraction of a Hz.
Further more these ICs can be integrated together to form more complex timer circuits that may be used for generating very long time intervals.
In this post we see how two different modes of ICs are coupled together to form a long duration timer circuit.
Referring to the circuit diagram.
IC1 is an oscillator counter IC consisting a built in oscillator stage and generates clock pulses with varying periods across its pins 1,2,3,4,5,6,7,9,13,14,15.
The output from pin 3 produces the longest time interval and therefore we select this output for feeding the next stage.
The pot P1 and the capacitor C1 of IC1 can be used for adjusting the time span at it pin 3.
The higher the setting of the above components the longer the period at pin #3.
The next stage consists of decade counter IC 4017 which does nothing but increase the time interval obtained from IC1 to ten folds. It means if the the time interval generated by IC1s pin #3 is 10 hours, the time generated at pin #11 of IC2 would be 10*10 = 100 hours. Similarly if the time generated at pin #3 of IC1 is 6 minutes, would mean a high output from pin#11 of IC1 after 60 minutes or 1 hour.
When power is switched ON, capacitor C2 makes sure that the reset pins of both the ICs are appropriately reset, so that the ICs begin counting from zero rather than from some irrelevant intermediate figure.
As long as the counting progresses, pin #11 of IC2 remains at logic low, such that the relay driver is held switched OFF.
After the set timing lapses, pin#11 of IC2 goes high activating the transistor/relay stage and the subsequent load connected with the relay contacts.
The diode D1 ensures that the output from pin#11 of IC2 locks the counting of IC1 by providing a feed back latch signal at its pin #11.
Thus the whole timer latches until the timer is switched OFF and restarted again for repeating the entire process.
Parts List
R1, R3 = 1M
R2, R4 = 1K,
C1, C2 = 1uF/25V,
D1, D2 = 1N4007,
IC1 = 4060,
IC2 = 4017,
T1 = BC547,
POT = 1M linear
RELAY = 12V SPDT
A simple timer can be built through many countless options. You can transistors, CMOS gates like NAND gates, NOT gates, linear ICs like 555, 741, 324, or simply more specific type of CMOS IC like the 4060.
All these devices besically generate oscillations which are adjustable right from a few Hz a second to a atomic fraction of a Hz.
Further more these ICs can be integrated together to form more complex timer circuits that may be used for generating very long time intervals.
In this post we see how two different modes of ICs are coupled together to form a long duration timer circuit.
Referring to the circuit diagram.
IC1 is an oscillator counter IC consisting a built in oscillator stage and generates clock pulses with varying periods across its pins 1,2,3,4,5,6,7,9,13,14,15.
The output from pin 3 produces the longest time interval and therefore we select this output for feeding the next stage.
The pot P1 and the capacitor C1 of IC1 can be used for adjusting the time span at it pin 3.
The higher the setting of the above components the longer the period at pin #3.
The next stage consists of decade counter IC 4017 which does nothing but increase the time interval obtained from IC1 to ten folds. It means if the the time interval generated by IC1s pin #3 is 10 hours, the time generated at pin #11 of IC2 would be 10*10 = 100 hours. Similarly if the time generated at pin #3 of IC1 is 6 minutes, would mean a high output from pin#11 of IC1 after 60 minutes or 1 hour.
When power is switched ON, capacitor C2 makes sure that the reset pins of both the ICs are appropriately reset, so that the ICs begin counting from zero rather than from some irrelevant intermediate figure.
As long as the counting progresses, pin #11 of IC2 remains at logic low, such that the relay driver is held switched OFF.
After the set timing lapses, pin#11 of IC2 goes high activating the transistor/relay stage and the subsequent load connected with the relay contacts.
The diode D1 ensures that the output from pin#11 of IC2 locks the counting of IC1 by providing a feed back latch signal at its pin #11.
Thus the whole timer latches until the timer is switched OFF and restarted again for repeating the entire process.
R1, R3 = 1M
R2, R4 = 1K,
C1, C2 = 1uF/25V,
D1, D2 = 1N4007,
IC1 = 4060,
IC2 = 4017,
T1 = BC547,
POT = 1M linear
RELAY = 12V SPDT
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