What can be cooked from squid: quick and tasty

Until now, some people use an hourglass to count down small periods of time. Watching the movement of grains of sand in such a watch is very exciting, but using it as a timer is not always convenient. Therefore, they are replaced by an electronic timer, the diagram of which is presented below.

Timer circuit

Making a timer

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The background is as follows: In the summer, flies are known to appear, mosquitoes, which interfere with sleep. Mosquitoes do not always enter the room, so there is no point in turning on the repellent every day. But when you go to bed and they start buzzing, you have to turn on the repeller. You fall asleep under it, and in the morning the wild stinks and the entire resource of the record are used up for one night. That's why it became necessary for me to cut the device (although my hands reached this only in winter), which turns off the load after a given time. I did not have the opportunity to buy a timer microcircuit, and the transistor relays had a very small delay. And the idea came to my mind do it yourself a time relay using a clock as a timer.

And let's start creating a relay with ... legs. I made them a punch from:

We glue the legs on plywood - the future base of the device:

We put the transformer:

And the standard body kit (diode bridge and capacitor) - as a result, we get an unstabilized power supply:

We received the power supply of the device, now it remains to figure out the circuit.

This diagram is for watches that have when the alarm goes off, it beeps for a short time:

When the "Start" button is pressed for a short time, relay 2 closes and holds the power supply circuit. The LED lights up, signaling the operation and relay 3 switches on the load. When the alarm goes off, relay 1 opens the power circuit and the contacts of relay 2 return to their original position. The load is disconnected. Instead of relays 2 and 3, one bipolar relay can be used.

For watches that have when triggered, the alarm clock is turned off only manually (i.e. it beeps constantly), the scheme is much simpler:

When the alarm signal is applied to the diode and emitter of the transistor, the relay contacts will be open - the load is disconnected. There will be no signal - enabled.

Relay 3 in the first circuit and relay 1 in the second must withstand the mains voltage and are designed for the current consumed by the load. Relays that are not suitable in terms of parameters will fail.

I got the relays from a broken uninterruptible power supply, 250v 5a - everything with a large margin.

We glue the reels:

Half of the work is done, now we need to deal with the clock.

It takes 3 volts to power the clock, but how do you get it?

Option 1- 3 volt stabilizer.

Option 2- Leave power on batteries.

Batteries are clearly not good, they can get hooked at the right time, so a stabilizer is preferable. If there is no stabilizer, then we use batteries.

I had a 5 volt regulator and connected it through 4 diodes. As a result, when the alarm goes off, there is a voltage drop, which is not good.

Although the load on the stabilizer is negligible, I fixed it on the radiator just in case. And at the same time it became more convenient to fix it in the watch case:

With a canopy I soldered a circuit that initiates the launch of the relyushka:

And I placed it all in the watch case:

The watch will be attached to the case covering the reels:

The final touch - we attach the outlet:

The device is ready. The scope of such a relay is limited by your imagination. For example, you can make an automatic watering plant or a pet food dispenser. Well, I fantasized ...

If anyone has a poor understanding of the principle of operation, watch this video. It prompted me to create a relay.

Demonstration of work:

The main component of the technical equipment of a modern house can be made do-it-yourself time relay... The essence of such a controller is to open and close the electrical circuit according to the specified parameters in order to control the presence of voltage, for example, in the lighting network.

Purpose and design features

The most perfect such device is timer consisting of electronic elements. Its actuation moment is controlled by an electronic circuit according to the specified parameters, and the relay release time itself is calculated in seconds, minutes, hours or days.

According to the general classifier, timers for turning off or turning on an electrical circuit are divided into the following types:

• Mechanical device.
• Timer with an electronic load switch, for example, built on a thyristor.
• The device operates on a pneumatic switch-off and switch-on drive.

Structurally, the actuation timer can be manufactured for installation on a flat plane, with a clamp on a DIN rail and for mounting on the front panel of the automation and indication switchboard.

Also, such a device, according to the method of connection, is front, rear, side and plugged in through a special detachable element. Time programming can be done using a switch, potentiometer or buttons.

As already noted, of all the listed types of devices for operating at a given time, the most popular is a time relay circuit with electronic shutdown element.

This is due to the fact that such a timer, operating from a voltage, for example, 12v, has the following technical features:

• compact dimensions;
• minimum energy costs;
• absence of moving mechanisms, with the exception of off and on contacts;
• widely programmable task;
• long service life, independent of operating cycles.

The most interesting thing is that the timer is easy to do with your own hands at home. In practice, there are many types of circuits that give a comprehensive answer to the question of how to make a time relay.

The simplest 12V timer at home

The simplest solution is time relay 12 volt... Such a relay can be powered from a standard 12v power supply, of which there are many sold in various stores.

The figure below shows a diagram of a device for turning on and off the lighting network, assembled on one integral counter of the K561IE16 type.

Drawing. A variant of the 12v relay circuit, when the power is applied, it turns on the load for 3 minutes.

This circuit is interesting in that it acts as a clock pulse generator. flashing LED VD1. Its blinking frequency is 1.4 Hz. If you cannot find an LED of this particular brand, then you can use a similar one.

Consider the initial state of operation, at the time of 12v power supply. At the initial moment of time, the capacitor C1 is fully charged through the resistor R2. Log.1 appears on the output under # 11, making this element zeroed out.

The transistor connected to the output integral counter, opens and supplies 12V voltage to the relay coil, through the power contacts of which the load switching circuit is closed.

The further principle of operation of a circuit operating at a voltage of 12V is pulse reading coming from the VD1 indicator with a frequency of 1.4 Hz to the contact number 10 of the DD1 counter. With each decrease in the level of the incoming signal, there is, so to speak, an increment in the value of the counting element.

Upon enrolment 256 pulses(this equals 183 seconds or 3 minutes) a log appears on contact # 12. 1. Such a signal is a command to close the transistor VT1 and interrupt the load connection circuit through the contact system of the relay.

At the same time, log.1 from the output under No. 12 is fed through the VD2 diode to the clock leg C of the DD1 element. This signal blocks in the future the possibility of receiving clock pulses, the timer will no longer be triggered, until the 12V power is reset.

The initial parameters for the trigger timer are set in different ways of connecting the transistor VT1 and the diode VD3, indicated in the diagram.

By slightly transforming such a device, you can make a circuit that has reverse operating principle... The KT814A transistor should be changed to another type - KT815A, the emitter should be connected to the common wire, the collector to the first contact of the relay. The second contact of the relay should be connected to the 12V supply voltage.

Drawing. A variant of the 12v relay circuit, turning on the load 3 minutes after power is applied.

Now after power on relay will be disabled, and the relay opening control pulse in the form of a logic 1 of the output 12 of the DD1 element will open the transistor and supply a voltage of 12V to the coil. After that, through the power contacts, the load will be connected to the electrical network.

This version of the timer, operating from a voltage of 12V, for a period of 3 minutes will keep the load in the disconnected state, and then connect it.

When making the circuit, do not forget to place a capacitor with a capacity of 0.1 μF, in the circuit having the designation C3 and a voltage of 50V, as close as possible to the supply pins of the microcircuit, otherwise the counter will often fail and holding time the relay will sometimes be less than it should be.

An interesting feature of the principle of operation of this scheme is the presence of additional features that, if possible, are easy to implement.

In particular, this is the programming of the holding time. Using, for example, such a DIP switch as shown in the figure, you can connect one switch contacts to the DD1 counter outputs, and combine the second contacts together and connect them to the connection point of the VD2 and R3 elements.

Thus, with the help of microswitches you can program holding time relay.

Connecting the connection point of elements VD2 and R3 to different outputs DD1 will change the holding time as follows:

Completing the circuit with elements

To make such a timer, operating at a voltage of 12v, it is required to properly prepare the circuit details.

The elements of the circuit are:

• diodes VD1 - VD2, marked 1N4128, KD103, KD102, KD522.
• A transistor that supplies a voltage of 12v to the relay - with the designation KT814A or KT814.
• Integrated counter, the basis of the principle of operation of the circuit, marked K561IE16 or CD4060.
• ARL5013URCB or L816BRSCB series LED device.

It is important to remember here that when making a homemade device, you must use the elements indicated in the diagram and follow the safety rules.

Simple circuit for beginners

Novice radio amateurs can try to make a timer, the principle of which is as simple as possible.

Nevertheless, with such a simple device, you can turn on the load for a specific time. True, the time for which the load is connected is always the same.

The algorithm of the circuit is as follows. When the button labeled SF1 is closed, the capacitor C1 is fully charged. When it is released, the specified element C1 begins to discharge through the resistance R1 and the base of the transistor, which is designated in the circuit - VT1.

For the duration of the discharge current of the capacitor C1, while it is sufficient to maintain the transistor VT1 in the open state, relay K1 will be on and then off.

The indicated ratings on the elements of the circuit ensure the duration of the load operation for 5 minutes. The principle of operation of the device is such that the holding time depends on the capacitance of the capacitor C1, the resistance R1, the current transfer ratio of the transistor VT1 and the operating current of the relay K1.

If desired, you can change the response time by changing the capacity C1.

Related Videos

To ensure accurate time intervals when performing various actions using electrical equipment, time relays are used.

They are used everywhere in everyday life: an electronic alarm clock, changing the operating modes of the washing machine, microwave oven, exhaust fans in the toilet and bathroom, automatic watering of plants, etc.

The advantages of timers

Of all the varieties, electronic devices are the most common. Their advantages:

• small size;
• extremely low energy consumption;
• no moving parts except for the electromagnetic relay mechanism;
• a wide range of time exposures;
• independence of service life from the number of working cycles.

Time relay on transistors

With the basic skills of an electrician, you can make an electronic time relay with your own hands. It is mounted in a plastic case, where the power supply, relay, board and control elements are located.

The simplest timer

The time relay (diagram below) connects the load to the power supply for 1-60 seconds. The transistor switch controls the electronic relay K1, which connects the consumer to the network with the contact K1.1.

In the initial state, the switch S1 closes the capacitor C1 to the resistance R2, which keeps it discharged. In this case, the electromagnetic switch K1 does not work, since the transistor is locked. When the capacitor is connected to the mains (upper position of the S1 contact), it starts charging. A current flows through the base, which opens the transistor and turns on K1, closing the load circuit. The supply voltage for the time relay is 12 volts.

As the capacitor charges, the base current gradually decreases. Accordingly, the value of the collector current falls until K1, by its shutdown, opens the load circuit with contact K1.1.

To reconnect the load to the mains for a specified period of operation, the circuit must be restarted again. To do this, the switch is set to the down position "off", which leads to the discharge of the capacitor. Then the device is switched on again with S1 within the set time interval. The delay is adjusted by setting the resistor R1, and can also be changed if the capacitor is replaced with another one.

The principle of operation of a relay using a capacitor is based on charging it over a period of time that depends on the product of the capacitance and the resistance value of the electrical circuit.

Timer circuit on two transistors

It is not difficult to assemble a time relay with your own hands on two transistors. It starts to work if you apply power to the capacitor C1, after which it will start charging. In this case, the base current opens the transistor VT1. Following it, VT2 opens, and the electromagnet closes the contact, supplying power to the LED. Its glow will show that the time relay has worked. The circuit provides load switching R4.

As the capacitor charges, the emitter current gradually decreases until the transistor turns off. As a result, the relay will be disconnected and the LED will stop working.

The device restarts if you press the SB1 button and then release it. In this case, the capacitor will be discharged and the process will be repeated.

Operation starts when power is applied to the 12V time relay. For this, stand-alone sources can be used. When powered from the mains, a power supply unit consisting of a transformer, rectifier and stabilizer is connected to the timer.

Time relay 220v

Most electronic circuits operate at low voltage with galvanic isolation from the mains, but they can switch significant loads.

The time delay can be made from a 220V time relay. Everyone knows electromechanical devices with a delayed shutdown of old washing machines. It was enough to turn the timer knob, and the device turned on the engine for a specified time.

Electromechanical timers have been replaced by electronic devices, which are also used for temporary lighting in the toilet, on the staircase, in a photographic magnifier, etc. In this case, proximity switches on thyristors are often used, where the circuit operates from a 220 V network.

Power is supplied through a diode bridge with a permissible current of 1 A or more. When the contact of the switch S1 closes, during the charging of the capacitor C1, the thyristor VS1 opens and the lamp L1 lights up. It serves as a load. When fully charged, the thyristor will close. This will be seen by turning off the lamp.

The lamp burns for a few seconds. It can be changed by installing a capacitor C1 with a different rating or by connecting a 1 kΩ variable resistor to diode D5.

Time relay on microcircuits

Transistor timer circuits have many disadvantages: the complexity of determining the delay time, the need to discharge the capacitor before the next start, and short response intervals. The NE555 microcircuit, called the "integral timer", has long gained popularity. It is used in industry, but you can see many schemes according to which do-it-yourself time relays are made.

The time delay is set by the resistances R2, R4 and the capacitor C1. The load connection contact K1.1 closes when the SB1 button is pressed, and then it opens independently after a delay, the duration of which is determined from the formula: t and = 1.1R2 ∙ R4 ∙ C1.

Pressing the button again repeats the process.

Many household appliances use time relay microcircuits. Instructions for use are a necessary attribute of correct operation. It is also compiled for DIY timers. Their reliability and durability depends on this.

The circuit operates from the simplest 12V power supply from a transformer, a diode bridge and a capacitor. The current consumption is 50 mA, and the relay switches the load up to 10 A. The adjustable delay can be made from 3 to 150 s.

Conclusion

For household purposes, you can easily assemble a time relay with your own hands. Electronic circuits work well on transistors and microcircuits. It is possible to install a non-contact timer on thyristors. It can be switched on without galvanic isolation from the current network.

The time relay is installed in many models of equipment and household appliances. This device allows you to automatically turn on or off the equipment and not waste time to control certain actions. Craftsmen often design various devices for their own needs. For many designs, it is required to make a do-it-yourself time relay, since branded devices are not always suitable in a particular situation. However, before starting to make a homemade timer, it is recommended that novice craftsmen familiarize themselves with the main types of such relays and the principles of their operation.

How does the electronic timer work

Unlike the very first timers with a clock mechanism, modern time relays are much faster and more efficient. Many of them are based on microcontrollers (MCs) capable of performing millions of operations per second.

This speed is not needed to turn on and off, so the microcontrollers were connected to timers capable of counting the pulses that occur inside the MC. Thus, the central processor executes its main program, and the timer ensures timely actions at specific intervals. Understanding the principle of operation of these devices will be needed even when making a simple capacitive time relay with your own hands.

Time relay working principle:

• After the start command, the timer starts counting from zero.
• Under the action of each impulse, the content of the counter increases by one and gradually reaches its maximum value.
• Further, the content of the counter is reset to zero, since it becomes "overflowed". At this moment, the time delay ends.

This simple design allows a maximum exposure time of 255 microseconds. However, in most devices, seconds, minutes and even hours are required, and therefore the question arises how to create the required time intervals.

The way out of this situation is quite simple. When the timer overflows, this event will interrupt the main program. Further, the processor goes to the corresponding subroutine, which adds up from small extracts any period of time that is required at the moment. This interrupt service routine is very short, consisting of no more than a few dozen instructions. At the end of its action, all functions return to the main program, which continues to work from the same place.

The usual repetition of commands does not occur mechanically, but under the guidance of a special command that reserves memory and creates short time delays.

The main types of time relays

When designing a homemade time relay, a specific model is taken as a sample. Therefore, every master must imagine the main devices that perform the functions of timers. The main task of any time relay is to obtain a delay between an input and an output signal. Various methods are used to create this delay.

Electromechanical relays include pneumatic devices. Their design includes an electromagnetic drive and a pneumatic attachment. The coil of the device is designed for alternating current with an operating voltage of 12 to 660 V - a total of 16 exact ratings are set. The working frequency is 50-60 Hz. With such parameters, a 12v time relay can be made by hand. Depending on the design, the shutter speed for such relays starts when the electromagnetic drive is triggered or when it is released.

The time is set using a screw that adjusts the cross-section of the hole through which air leaves the chamber. The parameters of these devices are not stable, therefore time relays have become more widespread.

These devices use a specialized microcircuit KR512PS10. Voltage is applied to it through a rectifier bridge and a stabilizer, after which the internal microcircuit generator begins to generate pulses. To adjust their frequency, a variable resistor is used, which is brought out to the front panel of the device and is connected in series with a capacitor that sets the time. The counting of the received pulses is carried out by a counter with a variable division ratio. These designs can be taken as a basis for making a cyclic time relay and other similar devices.

Modern time relays are made on the basis of microcontrollers and are unlikely to be suitable for home craftsmen as a sample. If it is necessary to obtain accurate time intervals, it is recommended to use the finished product.

Do-it-yourself time relay 220v circuit

Quite often, for designs made by home craftsmen, you need to make a simple do-it-yourself time relay. Reliable and inexpensive timers fully justify themselves during operation.

The basis of most home-made devices is the same KR512PS10 microcircuit, which is powered through a parametric stabilizer with a stabilization voltage of about 5 V. When the power is turned on, the chain consisting of a resistor and a capacitor forms a reset pulse for the microcircuit. At the same time, the internal generator starts up, in which the frequency is set by a chain of another resistor and capacitor. After that, the internal counter of the microcircuit starts counting pulses.

The number of pulses is also the division factor of the counter. This parameter is set by switching the pins of the microcircuit. When the output reaches a high level, the counter stops. At the other output, the pulses also reach a high level, as a result, VT1 opens. Through it, relay K1 is switched on, the contacts of which directly control the load. This circuit is ideal for solving the problem of how to make a 220v time relay with your own hands. To restart the time delay, it is quite sufficient to turn off the relay for a short time and then turn it on again.