Homemade timer. Timer connection diagram
---->
--->
The simplest cyclic timer. The simplest device for cyclically switching on and off the load.
My development Krylov P.V.Every winter the same problem arises. In severe frosts, the water supply from the well to the house freezes. This happens because the entrance to the house is made above the foundation. Although it is insulated with mineral wool, it freezes in severe frosts. This always happens at night when we are not using water. Accordingly, the pump does not turn on, the water is not pumped and freezes. A partial solution was found. At night they began to leave the cold water tap slightly open. But this doesn't always help. The valve axleboxes have a slight play and shut off the water at low pressure. This is how the idea of making a cyclic timer came about. A device that would turn on the pump for a few seconds and then hold it for several tens of minutes.
This device turns on the pump for 6 seconds after 20 minutes of exposure, then the cycle is repeated. Such a device can be used in ventilation systems, drip irrigation and other continuous-cyclic systems. Waiting and operating times can be varied within wide limits.
Analysis of what was on the Internet raised many questions.
I really liked the device in the article
But unfortunately, it is impossible to buy the K561IE5 microcircuit. Another article gave an overly complex diagram.
I chose the Kalashnikov principle. Extraordinary simplicity.
Note It is advisable to remove container C1. When checking, it turned out that this capacity does not have time to discharge when reset through the “AND” circuit.
The circuit is assembled on just one chip - a 14-bit counter CD4020, Russian analogue K561IE16.
The blinking LED is a generator with a frequency of approximately 3 pulses per 2 seconds.
At the input for supplying clock pulses C (pin 10) of the DD1 microcircuit there are pulses with a frequency of approximately 1.4-1.5 Hz. When the LED flashes at input C, the level is high, and when it goes out, this level changes to low. As the pulses fall at input C, counting begins. High levels appear at the counter outputs in accordance with the binary representation of the number of pulses arriving at the input. For example, if 16 pulses arrived at input C, then at output Q4 the pin of microcircuit No. 5 will appear 1 or a high level, all other pins will have “0”
After supplying power to the device, capacitor C1 begins to charge through resistor R2, a high level is set at the R input of the DD1 microcircuit, due to which a low level will be present at all its outputs.
The reset circuit does not work entirely correctly, because sometimes after switching on the outputs 1.
My introductions.
I introduced a logical element “AND” into the circuit.These are elements R5, D2, D3. If there is a 1 on pins Q3, Q11, then the “AND” circuit will work and the CD4020 chip will be reset. A high level at output Q11 will appear if 2048 pulses arrive at input C, which corresponds to approximately 21 minutes. At this moment, transistor VT1 will open and relay K1 will operate. The pump will turn on. After another eight pulses arrive at input C, which corresponds to 6 seconds, a high level will appear at output Q3, pin No. 7, and a reset will be triggered through the “AND” circuit. The pump will turn off. Then the counting cycle will repeat.
Details.
D5 any flashing LED.We will replace the flashing LED (except for the one indicated in the diagram) with L-816BRSC-B, L-56DGD, ARL-5013URC-B or similar. But in principle, any flashing LED will do.
Diodes D1, D2, D3, D6 - any of the KD521, KD522, KD102, KD103 or 1N4148 series. VD 4 any LED. It is used to indicate the operation of the meter. Changes its state every 8 pulses arriving at input C.
Relay K1 - any with an operating voltage of 10... 12 V.
Modification of the scheme.
If you switch diode D3 from pin 1 to pin 2 of the microcircuit, i.e. from Q11 to Q12, the shutter speed (pause) will double from 20 minutes to 40 minutes. If you switch from Q3 physical. pin 7 to Q4 physical. pin 5, then the operating time will double from 5-6 seconds to 10-12 seconds.
The scheme has been verified. Assembled on a breadboard. Video of the work below.
In the video tutorial of the channel “Reviews of parcels and homemade products from jakson” we will assemble a time relay circuit based on a timer chip on NE555. Very simple - there are few parts, so it won’t be difficult to solder everything with your own hands. At the same time, it will be useful to many.
Radio components for time relays
You will need the microcircuit itself, two simple resistors, a 3 microfarad capacitor, a 0.01 uF non-polar capacitor, a KT315 transistor, almost any diode, one relay. The device supply voltage will be from 9 to 14 volts. You can buy radio components or a ready-made time relay in this Chinese store.
The scheme is very simple.
Anyone can master it if they have the necessary parts. Assembly on a printed circuit board, which makes everything compact. As a result, part of the board will have to be broken off. You will need a simple button without a lock; it will activate the relay. Also two variable resistors, instead of one, which is required in the circuit, since the master does not have the required value. 2 megaohms. Two 1 megaohm resistors in series. Also, a relay with a supply voltage of 12 volts DC can pass through itself 250 volts, 10 amperes alternating current.
After assembly, this is what a time relay based on a 555 timer looks like.
Everything turned out compact. The only thing that visually spoils the appearance is the diode, since it has such a shape that it cannot be soldered otherwise, since its legs are much wider than the holes in the board. It still turned out pretty good.
Checking the device on a 555 timer
Let's check our relay. The operation indicator will be an LED strip. Let's also connect a multimeter. Let's check - press the button, the LED strip lights up. The voltage supplied to the relay is 12.5 volts. The voltage is now at zero, but for some reason the LEDs are on - most likely the relay is faulty. It is old, soldered from an unnecessary board.
By changing the position of the trimming resistors, we can adjust the operating time of the relay. Let's measure the maximum and minimum time. It turns off almost immediately. And maximum time. About 2-3 minutes passed - you can see for yourself.
But such indicators are only in the presented case. Yours may be different, since it depends on the variable resistor that you will use and on the capacitance of the electric capacitor. The larger the capacity, the longer your time relay will work.
Conclusion
Today we assembled an interesting device on the NE 555. Everything works great. The scheme is not very complicated, many will be able to master it without any problems. Some analogues of similar circuits are sold in China, but it is more interesting to assemble it yourself, it will be cheaper. Anyone can find a use for such a device in everyday life. For example, street light. You left the house, turned on the street lighting, and after some time it turned off by itself, just when you had already left.
Watch everything in the video about assembling the circuit on a 555 timer.
In this episode of the Soldering Iron TV channel, we'll look at a simple circuit. It is a simple timer, or time relay. It is made on just one active component in the form of a reverse bipolar transistor. The circuit is available for beginners and experienced radio amateurs for self-assembly. Radio parts are cheap in this Chinese store.
A few words about the element base. Diode D1 doesn't even need to be used. Replace with a jumper. If you decide to use, then any low-power diode, for example 1N4007, or any other rectifier diode. Capacitor C2 is selected if the device will be powered from a power supply. If from a battery, then there is no need for capacitor C2, since it is designed to filter the power. Resistors R2 and R1 with a power of 0.25 W. However, a not so powerful 0.125 W is possible. Capacitor C1 in the circuit has a capacity of 100 μF, but you need to select it. The operation time of the circuit depends on it. The voltage of this capacitor is 16-25 V, since our power supply itself is 12 V. Transistor T1 is any low-power bipolar transistor, reverse conductivity. You can even use KT315. The presented assembly uses a medium power transistor KT815A. You can also use high power transistors, for example KT805, KT803 even, KT819, and so on.
An electromagnetic relay winding is connected to the emitter circuit of the transistor to control powerful network loads. If you will use the circuit to power low-voltage low-power loads, for example, LEDs, then the relay can be removed and the LED itself can be connected directly to the emitter circuit.
How does the scheme work?
When you connect a power source, 12 V, for example, power is supplied to the circuit, and capacitor C1 is charged through the limiting resistor R2. And as soon as the charge on the capacitor has reached a certain level, power through resistor R1 is supplied to the base of the transistor. As a result, the latter opens, and the plus, through the transition of the transistor, is supplied to the winding of the electromagnetic relay. As a result, the latter closes, turning on or off the network load.
In the presented version, a regular 220 V incandescent lamp is used as a network load. If you want to control network loads, then pay attention to the relay parameters. Firstly, the relay coil must be designed for a voltage of 12 V. The contacts themselves must be quite powerful, depending, of course, on the connected load. That is, pay attention to the current allowed through the contacts.
The relay response time, that is, the capacitor charging time, largely depends on resistor R2. The higher its rating, the slower the capacitor will charge. And, of course, on the capacity of the capacitor C itself. The higher its rating, the longer it will take to charge, which means the longer it will take to charge and operate the circuit.
Let's consider the circuit in hardware.
The relay has a 12 V coil, this is indicated by the marking. Also, the permissible current through the contacts is 10 A at 250 V AC. The transistor does not heat up at all in the circuit. But since the circuit has a fairly large delay, with such a layout of the components used, it was decided to change the resistance R2. In the circuit, 47 kOhm was replaced by 4.4 kOhm, and this resulted in a delay of 2-3 s.
Let's connect to a 12 V power source. The following battery will be used, the exact voltage is somewhere around 10.8 V. These are three lithium banks connected in series. Pay attention to the LED. We have a blue LED connected through a 1 kOhm limiting resistor. As soon as the relay contacts are closed, power is supplied to the LED itself. Please note the delay. About 2 s. Of course, the circuit can remain on for an indefinitely long time.
This circuit can be used not only as a timer, but also as a Soft Start soft start system. A system of switching powerful power supplies is used. Why is it recommended to use soft start in powerful switching power supplies? Because when the circuit is connected to the network for a very short time, the circuit consumes exorbitant current. This happens because at the moment of switching on, the capacitors are charged with a high current. And as a result, other components of the circuit, for example, a diode bridge and so on, may not withstand such currents and fail. That's why this system is used.
How does a soft start system work in pulsed source circuits?
When connected to a 220 V network through a resistor that has some resistance and is current extinguishing, that is, it limits the current, a powerful capacitor is charged through this resistor with a low current. And as soon as the capacitors are fully charged, the relay is activated and the main power is supplied through the relay contacts to the switching power supply circuit. Thus, for example, you can select the charging time of the capacitor, adjust the response time here, and get a pretty good system for powerful switching power supplies. That's all. This is simple and accessible. Another simple diagram.
discussion
radmir tagirov
This is an example of how not to make a time relay. An inductive load must be bridged with a diode. Otherwise, one day your transistor will burn out. And why is the relay connected to the emitter?
Serghei
This is not a time relay, but a delay relay! And you put the diode in the wrong place!
Taras tsaryuk
But you don’t need to install a diode in parallel with a relay, right!? If you don’t mind the transistor, when the transistor closes and the relay is de-energized, there is such a thing as reverse current, and at that moment the transistor will get full. Well, in general, whatever. If you don't mind the details.
An_
I assembled such a circuit, only without a diode and a condenser at the input, and replaced the relay with an LED with a 300 kohm resistor connected in series, trans kt 3102, when connected to a battery of approximately 12V, the LED gradually begins to glow and shines, shines, shines! At lower voltage on the power source the picture is the same. I tried changing the condenser and resistors - the difference is in the speed at which the LED lights up. I thought it should light up and go out. Where is the mistake?
Zahar shoihit
This is really not a math lesson, but it seems to me that since the article is for beginners, it’s still worth explaining to people how to calculate the delay time.
Zahar shoihit
how did you get the two second delay?
After all, τ=rc 4. 4k*100µf=0. 44sec.
The 12 volt relay operates somewhere at 9v.
That is, 3/4 of the full charge of the capacitor.
3/4 of 5τ =(5*0. 44)/4*3=1. 65sec
This is ideal, but in theory even less.
gimbal youtube
Good day. Is it possible to assemble a 4-contact relay based on this circuit with sequential connection with a delay of 5 seconds? I would like to use something similar to accelerate a gantry crane.
Daria Novgorodova
guys, leave the person alone with your questions about the design of this relay. On my compressor it has been turning off the starting air conditioners for a year now. I use the compressor quite often. I also used it in alarm systems. So far there have been no problems.
Andrey f
I'm not a wizard, I'm just learning. Comrades, electronics engineers, please explain whether the base current of the transistor in this circuit does not appear immediately through r2, r1 and the coil. There is an assumption, as the author says, that the transistor opens with a delay of 2 seconds, when a voltage appears on the top plate as it charges, say 0.7 V, sufficient to open the transistor and the capacitance of the capacitor does not play a special role. Now, if there was a button with a folding contact between r2 and the connection point c1 and r1, then the size of the container would play a role in the long-term discharge. In short, can anyone please explain?
Sako grig
the voltage for opening the transistor 0.7 V appears in a few seconds, the time depends on the value of r2 and c1. When increasing the capacitance of the capacitor, 0.7 V will appear later, the same with increasing r2, since the charging current of the capacitor will decrease. I*t=c*u
Andrey F
Thanks for clarifying. I assembled the circuit into a multisim, using a 2n6488 transistor. The relay was connected to both the collector and the emitter. With a relay in the collector circuit, the circuit behaves approximately as you wrote on the basis of u = 0.5V, the opening current is 0.01mA. And when the relay in the emitter circuit is different, the voltage at the base is u= 4b, the current is 0.01 mA and the relay seems to operate at 4V. The resistance and capacitor were set differently, the charging time changed in both cases.
Sako grig
In general, I recommended connecting the relay to the collector circuit, grounding the emitter, replacing r1 with a zener diode of 3-4 volts (to increase the delay time), it is advisable to take a transistor with a large current gain - h21e.
Sako grig
I don’t think that multisim can understand the intricacies of the operation of different relay modifications, for example, some, although they are 12 volts, the operating voltage is 8-9 volts, and the release voltage can be somewhere around 3-4 volts.
Andrey f
It was interesting about 20 years ago when color TVs weighed 20 kg and to repair it you had to take it to a studio or call a repairman to your home, so I had to buy books myself and study this matter on my own, but my database is still too small since there wasn’t much advice to whom. Collect and see how the circuit works in multisim, why not. There are a lot of videos on the Internet, but there are very few that thoroughly explain the operation of the circuit. Here too, the author could show on a diagram the directions of currents, voltages on the capacitor, on the base of the transistor. Then there would be no questions about why the relay was placed in the emitter circuit and not the collector.
Stas stasovih
can you tell me the simplest diagram of a shutdown delay relay? Power supply is 24V, the delay after turning off the power is 60-120 seconds, I have all sorts of junk like PB from the computer, and small power supplies, is it possible to pull out the components from there?
Sako grig
it depends on what you mean when you say shutdown. If the shutdown is to turn off the 24-volt supply, then only the battery in the circuit will save, but if the shutdown must be done with a command button, there will be a different circuit.
Oleg Maltsev
it works? But as? When the base reaches 0.7V, the transistor will open and the supply voltage will appear at its emitter minus the drop voltage at the k-e junction, and in theory it should close until a voltage appears at the base that is 0.7V greater than the voltage at the emitter. In theory, the relay should be connected to the collector and a blocking diode should be added. Not?
alex lamin
and it’s not easier for everyone to label electrolytic capacitors in the same way with plus and minus, what is black and white, people need to look for it separately and spend time.
Alex lamin
hundreds of videos with the name time relay; to find out the on or off relay you need to watch the videos to the end. It wouldn’t be easier to write it in the title. People spend weeks searching. Not to mention the initial designation of any relay circuit. Where the coil is is not indicated either on the diagram or on the relay. Instead of the usual signs, let's say zero and phase, some kind of drawing with abstract thinking.
The main component of the technical equipment of a modern home can be made DIY time relay. The essence of such a controller is to open and close an electrical circuit according to specified parameters in order to control the presence of voltage, for example, in a lighting network.
Purpose and design features
The most advanced such device is timer consisting of electronic elements. Its moment of operation is controlled by an electronic circuit according to specified parameters, and the release time of the relay itself is calculated in seconds, minutes, hours or days.
According to the general classifier, timers to turn off or turn 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 operating principle of the device is based on a pneumatic drive to turn it off and on.
Structurally, the response timer can be manufactured for installation on a flat plane, with a lock on a DIN rail, and for mounting on the front panel of an automation and indication board.
Also, according to the connection method, such a device can be front, rear, side, or plugged in through a special detachable element. Time programming can be done using a switch, potentiometer or pushbuttons.
As already noted, of all the listed types of triggering devices for a given time, the greatest demand is for a time relay circuit with electronic shutdown element.
This is explained by the fact that such a timer, operating on voltage, for example, 12v, has the following technical features:
- compact dimensions;
- minimal energy costs;
- absence of moving mechanisms with the exception of switching and switching contacts;
- widely programmable task;
- long service life, independent of operation cycles.
The most interesting thing is that you can easily make a timer yourself at home. In practice, there are many types of circuits that provide 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 automatically turning off a lighting network, assembled on one integrated counter of the K561IE16 type.
Drawing. A variant of a 12v relay circuit that turns on the load for 3 minutes when power is applied.
This circuit is interesting in that it acts as a clock pulse generator flashing LED VD1. Its flicker frequency is 1.4 Hz. If you cannot find an LED of this particular brand, you can use a similar one.
Let's consider the initial state of operation, at the moment of supplying 12v power. At the initial moment of time, capacitor C1 is fully charged through resistor R2. Log.1 appears at pin No. 11, making this element zeroed.
Transistor connected to 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 the circuit operating at a voltage of 12V is as follows: pulse reading, coming from the VD1 indicator with a frequency of 1.4 Hz to contact No. 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.
On admission 256 pulses(this equals 183 seconds or 3 minutes) a log appears on pin No. 12. 1. This signal is a command to close transistor VT1 and interrupt the load connection circuit through the relay contact system.
At the same time, logic 1 from pin No. 12 is supplied through diode VD2 to clock leg C of element DD1. This signal blocks the possibility of receiving clock pulses in the future; the timer will no longer operate, until the 12V power supply is reset.
The initial parameters for the operation timer are set in different ways by 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 relay contact should be connected to a 12V supply voltage.
Drawing. A variant of a 12v relay circuit that turns on the load 3 minutes after power is applied.
Now after power on relay will be turned off, and the control pulse that opens the relay in the form of log.1 output 12 of element DD1 will open the transistor and supply a voltage of 12V to the coil. After which, the load will be connected to the electrical network through the power contacts.
This version of the timer, operating from a voltage of 12V, will keep the load disconnected for a period of 3 minutes, and then connect it.
When making the circuit, do not forget to place a capacitor with a capacity of 0.1 μF, designated C3 in the circuit and with a voltage of 50V, as close as possible to the supply terminals of the microcircuit, otherwise the meter will often fail and holding time the relay will sometimes be smaller than it should be.
An interesting feature of the operating principle of this scheme is the presence of additional capabilities, which, if possible, are easy to implement.
In particular, this is programming the exposure time. Using, for example, a DIP switch as shown in the figure, you can connect some contacts of the switches to the outputs of the counter DD1, and combine the second contacts together and connect them to the connection point of the elements VD2 and R3.
Thus, with the help of microswitches you can program holding time relay.
Connecting the connection point of elements VD2 and R3 to different outputs of DD1 will change the dwell time as follows:
| Counter leg number | Counter digit number | Exposure time |
|---|---|---|
| 7 | 3 | 6 sec |
| 5 | 4 | 11 sec |
| 4 | 5 | 23 sec |
| 6 | 6 | 45 sec |
| 13 | 7 | 1.5 min |
| 12 | 8 | 3 min |
| 14 | 9 | 6 min 6 sec |
| 15 | 10 | 12 min 11 sec |
| 1 | 11 | 24 min 22 sec |
| 2 | 12 | 48 min 46 sec |
| 3 | 13 | 1 hour 37 min 32 sec |
Complete set of circuit elements
To make such a timer operating at 12v voltage, you need to correctly prepare the circuit parts.
The elements of the scheme are:
- diodes VD1 - VD2, marked 1N4128, KD103, KD102, KD522.
- The transistor that supplies 12v voltage to the relay is designated KT814A or KT814.
- Integral counter, the basis of the operating principle of the circuit, marked K561IE16 or CD4060.
- LED device ARL5013URCB or L816BRSCB series.
It is important to remember here that when making a homemade device, you must use the elements indicated in the diagram and follow safety rules.
A simple scheme for beginners
Beginning radio amateurs can try making a timer, the principle of operation of which is as simple as possible.
However, 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 operating algorithm of the circuit is as follows. When the button labeled SF1 is closed, capacitor C1 is fully charged. When it is released, the specified element C1 begins to discharge through resistance R1 and the base of the transistor, designated VT1 in the circuit.
For the duration of the discharge current of capacitor C1, until it is sufficient to maintain transistor VT1 in the open state, relay K1 will be on and then off.
The indicated ratings on the circuit elements ensure that the load operates for 5 minutes. The operating principle of the device is such that the holding time depends on the capacitance of capacitor C1, resistance R1, current transfer coefficient of transistor VT1 and the operating current of relay K1.
If desired, you can change the response time by changing the capacitance C1.
Video on the topic
I have long been looking for some simple device to limit the operating time of various devices. There are a lot of timers sold, in China, too, with relays and all sorts of options. I even bought one of these, but I wanted simplicity. And this one caught my eye - C005.
The dimensions of the scarf are 12 by 12 millimeters. 
There is not a lot of information on the timer, but I found something and will briefly present it here. 
Supply voltage from 2 to 5 volts. Output current up to 30mA. It was not possible to record the current consumption in standby mode. Approximately 120 µA in operation. Switching circuit option. 
The time is set by an external resistor Rt. It works simply, controlled by TTL levels. Triggered by a fall (1-0 transition) at the trigger input - Trigger. The startup process is accompanied by the appearance of a low level at the output - Out, and after the specified time has elapsed it returns to a high state. During operation, the state of the trigger input does not affect the timer; it does not restart and runs for the specified time. Even maintaining a low level at the start input, after the specified time has expired, the timer does not start again. The dependence of time on resistance is presented in the table. 
The time varies slightly depending on the supply voltage. Maximum time approximately 2 hours. The table corresponds quite accurately to reality, I checked it with several resistances. There are two more pins on the board designated P1 and P2. If you close P1, then the time will increase by 8 times, if P2 by 64 times, and if both then by 512 times. This, as it is not difficult to calculate, is about 40 days.
A few words for what I want to use. First of all, I want to limit the operating time of a homemade street craft in the country. I bought a radio remote control for control. There is a relay in the control unit and, in principle, you can connect the spotlight to it directly, but I wanted to limit the operating time. In case someone forgets to turn it off. There is also some protection against accidental operation.
The scheme will look something like this.
Additional Information
In conclusion, I want to say that for the money the timer is very good. Minimum of attached parts and wide time range. You can come up with different options for use, everyone decides for themselves.
The downside is that the contacts are covered with some kind of crap and are not soldered, so I had to clean them with sandpaper. Planning to buy +109 Add to favorites I liked the review +111 +176