AC Power Outlet with Timer Circuit

Consider a standard plug that plugs into a wall socket and has a timer built right in, like a control panel.

This is known as a timer plug or outlet timer.

Another appliance can be plugged into it.

The integrated circuit, especially a 555 timer, is the timers little brain.

That is the cool part, sending electricity in square wave pulses, this integrated circuit functions as an extremely quick switch.

The speed of this square wave is controlled by varying resistors and a capacitor, which resemble small knobs and a tiny battery holder.

The device hooked into the timers on and off cycles are determined by this speed.

These component values can even be used by online calculators to determine the frequency (or how frequently the pulse occurs) and time period (or how long the appliance is on or off).

So, due to this little timer with its built in brain, you can use an outlet timer to program your lamp to turn on at sunset and switch off at sleep, or to have your christmas lights twinkle on a schedule!

Circuit Working:

Parts List:

By using the wall outlets AC power straight from the home this design eliminates the need for a step down transformer.

This is how the circuit works:

AC Subduing:

Together, resistor R3 and capacitor C4 lower the AC voltage.

By acting as a shield C4 resists abrupt voltage fluctuations (capacitive reactance).

When the power is out, R3 aids in the discharge of C4.

Converting AC to DC:

The decreased AC voltage is transformed into pulsing DC by the bridge rectifier.

Control of Voltage:

By acting as a voltage regulator, the zener diode maintains a constant DC voltage of about 9V.

Any residual oscillations in the DC supply are further attenuated before they reach the timer circuit by capacitor C3.

Control and Timing:

The configuration of the 555 timer chip is an astable multivibrator.

It can produce continuous square wave pulses in this mode, which regulates the on and off timings.

The length of these on and off cycles may be altered by altering resistors R2 and capacitor C1.

Power Transfer:

Between the neutral line and the AC power outlet, a TRIAC BT136 serves as a switch.

Its gate terminal is linked to the 555 timers output pin.

The TRIAC activates in response to a high voltage pulse sent by the timer letting electricity to flow to the outlet for the predetermined amount of time.

On the other hand, the TRIAC cuts off and the outlet loses power when the timer transmits a low voltage pulse.

With this configuration, any device hooked into the timer outlet will automatically go into an on/off cycle.

The circuit provides an on time of about 23 minutes and an off time of 23 minutes with the present component values.

If you just require an automated shut off feature, you can adjust the timer circuit to a monostable state.

Formula:

Resistors, capacitors, transistors, integrated circuits and potentially a triac for AC load switching are used to create an astable multivibrator circuit with a timer for controlling AC power.

This is a simple schematic and formula for creating a circuit of such a kind.

In the diagram above assume that R1 and R2 are the resistors and assume that C1 and C2 are the capacitors.

For both the HIGH and LOW states of the astable multivibrator, the approximate time interval T is provided by:

T = 0.693 × (R1 + R2) × C1

This formula establishes the multivibrators oscillation frequency, which affects when your AC load turns on and off.

In order to manage an AC power outlet, an astable multivibrator circuit with a timer can be designed using the fundamental formula and considerations listed in this description.

Depending on the needs of your particular application, modifications to component values and extra circuitry could be required.

How to Build:

To build a AC Power Outlet with Timer follow the below mentioned steps for connections:-

• Gather all the components mentioned in the diagram above.
• Connect pin 1 of IC1 555 to ground.
• Connect pin 2 to pin 6 of IC1 555.
• Connect pin 3 of IC1 555 to gate of triac1 through resistor R4 and LED1.
• Connect pin 4 of IC1 555 to positive supply.
• Connect pin 5 of IC1 555 to ground through capacitor C2.
• Connect pin a resistor R2 between pin 7 and pin 6 and pin 2 of IC1 555.
• Connect pin 7 of IC1 555 to positive supply through resistor R1.
• Connect capacitor C1 to ground from pin 6 and pin 2 of IC1 555.
• Connect pin 8 of IC1 555 to positive supply.
• Connect a capacitor C3 from positive supply to ground.
• Connect a zener diode 9V 1W from positive supply to ground.
• Connect a capacitor C4 and resistor R3 in series with AC line to drop current for the IC 555 circuit.
• Connect a bridge rectifier using 4 nos of diodes 1N4007 to convert the low current AC from R3 and C4 to DC.
• Connect triac1 MT1 to ground, connect MT2 to one end of mains socket and other end of socket to 230V AC, connect gate to pin 3 of IC1 555.

Safety Measures:

• Developing circuits using mains AC power necessitates a solid grasp of electrical theory and safety procedures.
• If handling high voltage makes you uncomfortable think about getting assistance from a licensed electrician.
• Make sure that every component including the TRIAC, resistors and capacitors is rated for the AC voltage and current you want to use, using parts that are not rated properly might catch fire.
• Always unplug the electricity from the outlet before working on the circuit, check again before handling any parts.
• Ensure that the circuit box is adequately grounded to avoid any shocks in the event of a malfunction.
• Although this circuit presents an intriguing method of controlling appliances, improper handling of its direct interaction with mains AC electricity can be hazardous.

Conclusion:

To conclude, With the help of this AC Power Outlet with Timer design, appliances may be directly powered by mains AC power and controlled by a 555 timer.

Although this design shows off an intriguing use for the 555 timer safety should always come first.

If handling high voltage makes you uncomfortable think about safer options or get assistance from a licensed electrician.

References:

Time switch