Homemade timer 220V. Simple electronic timer

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, given the availability necessary details. 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, supply voltage 12 volts direct current, can pass through itself 250 volts, 10 amperes alternating.

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 LED Strip Light. 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. Application similar device Anyone can find it in everyday life. For example, street light. You left the house, turned on street lighting and after some time it turns itself off, just when you leave.

Watch everything in the video about assembling the circuit on a 555 timer.

Clock with audible alarm timer for controlling household appliances.

A timer is a device that set time turns the equipment on or off with its switching contacts. Real-time timers allow you to set the trigger time at a set time of day. The most simple example such a timer will be an alarm clock.

The scope of application of the timer is extensive:
- lighting control;
- watering control for households and garden plants;
- ventilation control;
- aquarium management;
- control of electric heaters and so on.

The proposed timer can be made quickly and inexpensively even by a novice radio amateur.
I made it based on the clock designer. ()

I needed to use a timer to control the watering of plants at the dacha.

Watch the entire manufacturing process in the video:

List of tools and materials
- any electronic watch with an alarm sound;
-screwdriver;
- scissors;
- soldering iron;
-cambric;
- two 12V relays;
-12V power supply from adapter;
- connecting wires;
- foil PCB for a printed circuit board or breadboard;
-industrial or homemade time relay;
-resistor;
- transistors KT815 (or analogues);
-diode.

Step one. Timer board wiring.
Timer circuit
All that is needed is to solder the components according to the diagram onto a breadboard and solder two wires from the piezo emitter of the clock. We collect the simplest scheme with intermediate relay and transistor switch. When the first pulse of a sound signal is sent from the clock, relay P1 is turned on, the normally open contact closes and turns on the load, and at the same time, through the second normally open contact of relay P1 and the normally closed contact of the time relay, relay P1 self-locks. Together with the load, the time relay PB is turned on - the countdown of the specified load operating time begins. At the end of this time, RV opens the contact and relay P1 is de-energized, the load is turned off. The circuit is ready for the next cycle. The diode serves to prevent a reverse pulse into the clock circuit (any low-power diode can be used). LED to indicate load activation. In this circuit, you need an intermediate relay with two normally open contacts, but I didn’t have one - I used two Chinese relays (the coils are connected in parallel). If the load is more powerful, then accordingly you need to use a relay with more powerful contacts. I had a 12V adapter and installed its circuit directly on the breadboard. In principle, any low-power 12V power source can be used.

In short, the clock turns on the load and the time relay is turned off after the delay has expired.
If you do not have an industrial time relay, you can make it yourself using a simple scheme. As the capacitance of capacitor C1 increases, the operating time of the relay increases.

Step two. Checking the timer operation.
My circuit worked the first time I turned it on.
All that remains is to set the alarm time. My watch has two alarm time settings. For my case, it’s enough to turn on watering, for example, in the morning at 7 o’clock for one hour, and in the evening at 20 o’clock, water again. When you press the clock buttons, sound signals are emitted, so when setting, the timer circuit must be de-energized to prevent false alarms. My watch has a “chime” function - every hour from 8 to 20 o’clock, that is, in addition to the alarm clock, you can use these signals if necessary. If not necessary, then the “chimes” function is disabled.

This is how the weekend design turned out. It was interesting to test out the new scheme, so everything was done quickly. In the future, it will be necessary to make a case and place a board and a time relay there. A beginner can make such a timer on his own without spending a lot of time and money. And where to use them is up to you to decide.

All the work took a couple of weekend evenings and 75 rubles (

Timer circuit on the K561IE16 counter

The design is made on only one chip K561IE16. Since, for him proper operation If we need an external clock generator, in our case we will replace it with a simple blinking LED.

As soon as we apply power to the timer circuit, the capacitance C1 will start charging through the resistor R2 therefore, a logical one will briefly appear at pin 11, resetting the counter. The transistor connected to the meter output will open and turn on the relay, which will connect the load through its contacts.

With a flashing LED with a frequency 1.4 Hz pulses are sent to the clock input of the counter. With each pulse drop the counter counts. Through 256 pulses or about three minutes, a logical one level will appear at pin 12 of the counter, and the transistor will close, turning off the relay and the load switched through its contacts. In addition, this logical unit passes to the DD clock input, stopping the timer. The operating time of the timer can be selected by connecting point “A” of the circuit to various outputs of the counter.

The timer circuit is implemented on a microcircuit KR512PS10, which has in its internal composition a binary counter-divider and a multivibrator. Like a conventional counter, this microcircuit has a division coefficient from 2048 to 235929600. The selection of the required coefficient is set by applying logical signals to the control inputs M1, M2, M3, M4, M5.

For our timer circuit, the division factor is 1310720. The timer has six fixed time intervals: half an hour, an hour and a half, three hours, six hours, twelve hours and a day of an hour. The operating frequency of the built-in multivibrator is determined by the resistor values R2 and capacitor C2. When switch SA2 is switched, the frequency of the multivibrator changes, and passing through the counter-divider and the time interval.

The timer circuit starts immediately after turning on the power, or you can press the SA1 toggle switch to reset the timer. In the initial state, the ninth output will have a logical one level and the tenth inverse output, respectively, a zero. As a result of this, the transistor VT1 connects the LED part of the optothyristors DA1, DA2. The thyristor part has an anti-parallel connection, this allows you to regulate the alternating voltage.

Upon completion of the time countdown, the ninth output will set to zero and turn off the load. And at output 10 a unit will appear, which will stop the counter.

The timer circuit is launched by pressing one of three buttons with a fixed time interval, and it begins to count down. In parallel with pressing the button, the LED corresponding to the button lights up.

When the time interval expires, the timer emits a sound signal. A subsequent press will turn off the circuit. Time intervals are changed by the ratings of radio components R2, R3, R4 and C1.

Timer circuit, which provides a turn-off delay, is shown in the first figure. Here, a transistor with a p-type channel (2) is connected to the load power circuit, and a transistor with a n-type channel (1) controls it.

The timer circuit works as follows. In the initial state, capacitor C1 is discharged, both transistors are closed and the load is de-energized. When you briefly press the Start button, the gate of the second transistor is connected to the common wire, the voltage between its source and gate becomes equal to the supply voltage, it instantly opens, connecting the load. The voltage surge that appears on it through capacitor C1 is supplied to the gate of the first transistor, which also opens, so the gate of the second transistor will remain connected to the common wire even after the button is released.

As capacitor C1 is charged through resistor R1, the voltage across it increases, and at the gate of the first transistor (relative to the common wire) decreases. After some time, depending mainly on the capacitance of capacitor C1 and the resistance of resistor R1, it decreases so much that the transistor begins to close and the voltage at its drain increases. This leads to a decrease in the voltage at the gate of the second transistor, so the latter also begins to close and the voltage across the load decreases. As a result, the voltage at the gate of the first transistor begins to decrease even faster.

The process proceeds like an avalanche, and soon both transistors close, de-energizing the load, capacitor C1 quickly discharges through diode VD1 and the load. The device is ready to start again. Because field effect transistors Assemblies begin to open at a gate-source voltage of 2.5...3 V, and the maximum permissible voltage between gate and source is 20 V, then the device can operate with a supply voltage from 5 to 20 V (the nominal voltage of capacitor C1 should be several volts more than the supply). The shutdown delay time depends not only on the parameters of elements C1, R1, but also on the supply voltage. For example, increasing the supply voltage from 5 to 10 V leads to its increase by approximately 1.5 times (with the nominal values ​​of the elements indicated in the diagram, it was 50 and 75 s, respectively).

If, with the transistors closed, the voltage across resistor R2 is more than 0.5 V, then its resistance must be reduced. A device that provides a switch-on delay can be assembled according to the circuit shown in Fig. 2. Here the transistors of the assembly are connected in approximately the same way, but the voltage to the gate of the first transistor and capacitor C1 is supplied through resistor R2. In the initial state (after connecting the power source or after pressing the SB1 button), capacitor C1 is discharged and both transistors are closed, so the load is de-energized. As R1 and R2 charge, the voltage across the capacitor rises, and when it reaches approximately 2.5 V, the first transistor begins to turn on, the voltage drop across R3 increases, and the second transistor also begins to turn on. When the load voltage increases so much that diode VD1 opens, the voltage across resistor R1 increases. This leads to the fact that the first transistor, and then the second one, opens faster and the device abruptly switches to the open state, closing the load power circuit

The timer circuit is a restart, for this you need to press the button and hold it in this state for 2...3 s (this time is enough to completely discharge capacitor C1). Timers are mounted on printed circuit boards made of fiberglass foil on one side, the drawings of which are shown in Fig. 3 and 4. The boards are designed for the use of diodes of the KD521, KD522 series and surface mounting parts (resistors R1-12, size 1206 and tantalum oxide capacitor). Setting up devices comes down mainly to selecting resistors to obtain the required time delay.

The described devices are designed to be included in the positive power supply wire of the load. However, since the IRF7309 assembly contains transistors with both channel types, the timers can easily be adapted to be included in the negative wire. To do this, the transistors should be swapped and the diode and capacitor switched on in reverse polarity (of course, this will require corresponding changes in the printed circuit board drawings). It should be taken into account that if the connecting wires are long or there are no capacitors in the load, interference on these wires and uncontrolled activation of the timer is possible. To increase noise immunity, a capacitor with a capacity of several microfarads with a rated voltage of at least the supply voltage must be connected to its output.

Five minute timer circuit

If the time interval is more than 5 minutes, the device can be restarted and continue counting again.

After a short circuit of SВ1, capacitance C1, connected to the collector circuit of transistor VT1, begins to charge. The voltage from C1 is supplied to an amplifier with a high input resistance on transistors VT2-VT4. Its load is led indicator, turning on alternately every minute.

The design allows you to choose one of five possible time intervals: 1.5, 3, 6, 12 and 24 hours. The load is connected to the AC network at the time the countdown begins and is disconnected when the countdown ends. Time intervals are set using a frequency divider of square wave signals generated by an RC multivibrator.

The master oscillator is made on the logical components DD1.1 and DD1.2 of the microcircuit K561LE5. The generation frequency is formed by an RC circuit on R1,C1. The accuracy of the stroke is adjusted according to the shortest time interval, using the selection of resistance R1 (it is advisable to temporarily replace it when adjusting variable resistance). To create the necessary time ranges, pulses from the multivibrator output go to two counters DD2 and DD3, as a result of which the frequency is divided.

These two counters - K561IE16 are connected in series, but for simultaneous reset, the zeroing pins are connected together. Reset occurs using switch SA1. Another toggle switch SA2 selects the required time range.

When a logical one appears at the output of DD3, it goes to pin 6 of DD1.2, as a result of which the generation of pulses by the multivibrator ends. At the same time, the logical one signal goes to the input of the inverter DD1.3 to the output of which VT1 is connected. When a logical zero appears at the output of DD1.3, the transistor closes and turns off the LEDs of the optocouplers U1 and U2, and this turns off the triac VS1 and the load connected to it.

When the counters are reset, their outputs are set to zero, including the output to which switch SA2 is installed. A zero is also supplied at the input of DD1.3 and, accordingly, a unit at its output, which connects the load to the network. Also in parallel, the zero level will be set at input 6 of DD1.2, which will trigger the multivibrator and the timer will begin counting. The timer is powered using a transformerless circuit consisting of components C2, VD1, VD2 and C3.

When toggle switch SW1 is closed, capacitor C1 begins to slowly charge through resistance R1, and when the voltage level on it is 2/3 of the supply voltage, trigger IC1 will respond to this. In this case, the voltage at the third terminal will drop to zero, and the circuit with the light bulb will open.

With a resistance of resistor R1 of 10M (0.25 W) and capacitance C1 of 47 µF x 25 V, the operating time of the device is about 9 and a half minutes, if desired, it can be changed by adjusting the values ​​of R1 and C1. The dotted line in the figure indicates the inclusion of an additional switch, with which you can turn on the circuit with the light bulb even when the toggle switch is closed. The design's quiescent current is only 150 μA. Transistor BD681 - compound (Darlington) medium power. Can be replaced with BD675A/677A/679A.

This is a timer circuit on a PIC16F628A microcontroller, borrowed from a good Portuguese site on radio electronics. The microcontroller is clocked from an internal oscillator, which can be considered quite accurate for this moment, since pins 15 and 16 remain free, you can use an external quartz resonator for even greater accuracy in operation.

Time relay with remote control.

The 555 time relay can be supplemented with a system remote control for ease of use. You can add the ability to turn on the relay by pressing any button on any remote control that emits pulses of infrared radiation (such remote controls are mainly used to control televisions and other household appliances). The diagram of a time relay supplemented with an infrared radiation receiver is shown in Figure 1.

Fig.1

Capacitor C2 is needed to prevent false alarms from interference that occurs when switching the load through relay K1. The photodiode must be placed in a black box with a window. To configure, power is supplied and resistor R2 sets the voltage at pin 2 of the microcircuit slightly greater than the voltage Up/3 where Up is the supply voltage. If the voltage at pin 2 of the 555 chip is less than Up/3, then the relay will be turned on. If the voltage at pin 2 of the 555 microcircuit is less than Up/3 constantly, then the relay will be constantly on.

This relay can be used to switch many different devices.

Periodic automatic switching on/off of devices.

Scheme for periodic automatic switching on/off of devices, in particular a fan for ventilation, etc. can be done on a 555 NE555 timer. The diagram is shown in Figure 2.

Fig.2

The relay turns on and closes the power source to the load only when there is a low voltage level at the output of the microcircuit, the flowing current from the base of transistor VT1 will become sufficient for this transistor to enter saturation, this transistor will not burn out, since the relay winding has sufficient active resistance , so that the current through the transistor is less than the maximum permissible for KT209K.

Timer on NE555 chip

Figure 3 shows the diagram simple relay time on NE555.

Fig.3

With the specified elements, the time relay operates in the time interval from 1 to 100 seconds. The relay response time is set by potentiometer R2. The capacitance of capacitor C1 determines the main range of relay response time (100 seconds); by decreasing or increasing the capacitance, other time intervals can be achieved.

Time relay

Time relays are designed for switching electrical circuits of devices with a given time delay. The described time relays do not contain a network transformer, therefore they can significantly reduce their weight and overall dimensions. When setting up and operating the relay, precautions must be taken, since the circuits and elements of these devices are under mains voltage. If it is necessary to ensure that there is no galvanic connection with the network, then the easiest way is to power the time relay through an isolation transformer of appropriate power.

Fig.4

In Fig. 4 shown circuit diagram time relay with load in the form lighting lamps incandescent Such relays can be installed in corridors, staircases, hallways in order to save electrical energy and increasing lamp life.

The time relay contains a thyristor (triode thyristor) VS1 and a timing unit on the transistor VT1, which controls the operation of the thyristor. In the initial state, capacitor C1 is charged to the mains voltage, the transistor and thyristor are closed. When you press the S1 button, capacitor C1 is discharged through resistor R5 and diode VD3. In every positive half-cycle mains voltage the capacitor is charged through the emitter junction of the transistor VT1, as a result, the thyristor VS1 opens and turns on the lamp H1. During the negative half-cycle of the voltage, no current flows through the device.

After releasing the button, at each positive half-cycle of the voltage, the current through diodes VD1, VD2, resistor R4 and the emitter junction of transistor VT1 recharges capacitor C1 and the lamp intensity gradually decreases. The time of each charging pulse is approximately equal to the opening time of the thyristor. Thanks to this, with a relatively small capacitance of capacitor C1 and the resistance of resistor R4, it was possible to obtain a significant charging time constant. After the capacitor is fully charged, the current through the transistor stops and the thyristor closes. The required time delay for turning off the lamp is set by adjusting resistor R3.

The maximum time delay of the relay to turn off the lamp is about 10 minutes. At the end of the exposure, the lamp intensity begins to decrease. In standby mode, the device does not consume power from the network.

The time relay can use any diodes from the KD105 series or D226B diodes. A transistor is required with a maximum permissible collector-emitter voltage of 300 V. It is advisable to select capacitor C1 in a sealed design. Thyristor VS1 must be designed for a reverse voltage of at least 300 V.

Timer on NE555 chip

The timer circuit shown in Fig. 5 is based on the NE555 chip.

Fig.5

Pressing the SB1 button starts the timer, which is indicated by the HL1 LED. After the set time has passed, HL2 lights up. If you install a relay instead of the second LED, you can significantly expand the scope of the device. Resistor R2 adjusts the timer operation time.

Timer with LED indication

Fig.6

This circuit (Fig. 6) can be used to control cooking time, in a darkroom or as part of another circuit. The delay time can be from a few seconds to 5 minutes. and depends

on the capacitance value of capacitor C1.

Koval V.A.

Chernigov

Time relay on a triac

The circuit shown in Fig. 7 allows you to directly (without a relay) control the disconnection of the network load.

Fig.7

A triac is used as a switch. The load will turn on when you initially connect to the network or when you press the button S.B. 1. To power the microcircuit, reactance is used, which is capacitor C1. Zener diode VD 1 provides a stable supply voltage to the microcircuit, diode VD 3 allows you to reduce the readiness time of the circuit for frequent pressing of the button. The turn-off delay time can be adjusted by a resistor R 3 from 0 to 8.5 min. Timing capacitor C3 must have a small leakage.

Shelestov I.P.

For radio amateurs: useful

scheme

Load control timer

The time relay, the diagram of which is shown in Fig. 8, is designed to control one load - turning on an electrical appliance or turning it off after some time, which must pass from the moment the “Start” button is pressed. This time, with the values ​​C2, R2 and R3 indicated in the diagram, can be set using R3 in the range from 15 minutes to 10 hours.

Fig.8

The peculiarity of the relay is that after the set time delay has been completed and the relay turns on or off the load, the relay will automatically disconnect from the power supply, and it will be turned off until the next press of the “Start” button.

The presence of a simple electromagnetic relay at the output makes it possible to control any load.

The role of the timing unit is assigned to the D1 microcircuit, which contains multivibrator elements and a binary counter.

In this circuit, the RC circuit together with the microcircuit counter allows you to obtain almost any shutter speed from 1 second to several days, it all depends on the parameters of this RC circuit, the capacitive component of which can be from 50 pF to several μF, and the resistance from 10 kOhm to several MOhm .

In this case, with capacitance C2 equal to 0.33 mKF, and resistance R2 + R3 within 100 kOhm... 2.3 MOhm, you can obtain shutter speeds from 15 minutes to 10 hours. By changing the parameters of this circuit, you can get other shutter speeds.

The time relay is turned on and started using the S1 button, which does not have a fixation.

By adjusting R3, you set the time during which, after pressing the S1 button, the relay will be automatically maintained in the state connected to the power supply.

Now let's talk about how the load is connected. There can be two options: in the first, the load is turned on after the set time has elapsed, in the second, the load is turned on immediately when you press S1, and turns off after the set time has passed. The option is selected using toggle switch S2.

In the position shown in the diagram, after pressing S1, the load is turned off, and is turned on only after the time relay has completed its time delay and the contacts of relay P1 return to their original position. In the "OFF" position of toggle switch S2, the load is turned on simultaneously with pressing S1 and turned off simultaneously with the relay turning off, that is, it works only for the set time.

As relay P1, an automobile relay "112.3747-10E" from a VAZ-2108 is used, which has a group of switching contacts. The relay was chosen for reasons highest power contacts so that you can control any load, including electric heating devices.

Simple household timer

The circuit diagram of the timer is shown in Figure 9.

Fig.9

The time interval is set with a variable resistor R 4, which regulates the pulse frequency of the internal multivibrator of the microcircuit. And then these pulses are read by the counter. And after it counts 8192 of them, relay P1 is turned off and the multivibrator is turned off using a diode VD 1.

Start the timer with the button S 1 (press and release). When the button is pressed, through its contacts to pin 12 (zeroing input R ) the level voltage is supplied to a logical unit. This sets the counter to the zero position when all its pins are logic zeros. The highest output (pin 3) will also have zero.

Transistor switch on VT 1 and VT 2 made on transistor structures p-n-p , therefore, to open it to the base VT 1, you need to apply a negative voltage relative to the emitter, that is, a logical zero. This occurs when the counter is set to zero. And then, the key opens and supplies current to relay K1, the contacts of which move and either turn off the load or turn it off.

After releasing the button S 1 input voltage R the counter drops to logical zero and the counter will be able to count the pulses generated by the multivibrator, the external parts of which are C 2, R 2, R 4, R 3.

With the arrival of the 8192nd pulse (from the moment the button is released S 1) a logical one appears at pin 3 of the microcircuit. This leads to the closing of the transistor switch and turning off the electromagnetic relay. At the same time, the multivibrator is blocked through a diode VD 1. The counter stops in this position and will remain there until the button is pressed again S 1 (or until the power is turned off).

The period of time during which relay P1 is turned on is set with a variable resistor R 4. Resistor R 2 limits the minimum resistance of the timing resistance. When the resistor R 4 is set to the minimum position (far left, according to the diagram), the time interval worked by the timer is about 27 minutes. At extreme right position R 4, - 170 minutes. You can reduce the shutter speed by half if the connection point of the resistor R 6 and diode VD 1 switch from pin 3 D 1 to pin 2. And if this point is switched to pin 1, the set shutter speed will decrease by four times. You can make a switch with positions “1/1”, “1/2” and “1/4”.

You can make it so that the load will turn on periodically (for example, it works for 27 minutes, rests for 27 minutes), for this you need to remove the diode from the circuit VD 1.

Whether the load turns on or off depends on which relay outputs are connected to its power supply.

The relay winding is a fairly powerful load, so the timer is powered not from a battery, but from a network source. For example, relay WJ 118-1 C can include a load powered by a voltage of up to 250 V at a current of up to 5 A. And the rated voltage of the relay winding is 12 V. That is, the timer can control a network load with a power of up to 1250 W.

Transistors KT361 can be replaced with KT3107, KT502. Transistor KT814 - to KT816. All diodes - KD522, KD521, 1 N4148.

Universal timer

This timer is made analogue - digital circuit, it can be used to delay turning on or off various electrical equipment, Fig. 10.

Fig.10

The timer can handle any shutter speed ranging from 2 seconds to 3 hours. The required time is set using a variable resistor R 3 and switch S 1. The resistor regulates the frequency of the clock generator, and the switch switches the division ratio of the counter. This results in two ranges “2 sec... 2.4 min” and “90 sec...3 hours”. Ranges are selected by switch S 1 (“M”-“H”). To set the shutter speed, there are two round scales around the handle of the variable resistor, and the handle has an arrow. Of course, this method does not provide great accuracy in setting the time, since the ranges are wide, the scales are short, and variable resistor the thing is unstable, but this timer is intended for those cases when the time needs to be set “somewhere like that, approximately...”. And there are many such cases in practice.

The timer output is relay. This allows you to control almost anything; it is important that the load power does not exceed the permissible value for the contacts of a given relay.

The circuit is based on a microcircuit CD 4060 B and it contains a counter type K561IE16, and also inverters for quartz or R.C. -multivibrator.

The timer is powered from a 12V source. In general, the value of this voltage can be from 5 to 15V and depends primarily on the rated voltage of the winding of the relay used.

Chip CD 4060 B can be replaced with a similar microcircuit from other manufacturers, for example, M.P.J. 4060. Domestic analogue No. Relay BS 115 C with a 12V winding can be replaced with a similar one with a 5,6,9V winding, and the supply voltage will change accordingly. Or, if you need to maintain a 12V supply voltage, connect a resistor in series with the relay winding, which will absorb the excess voltage. Its resistance can be selected experimentally or calculated, knowing the resistance of the relay winding and its rated voltage.

If the relay is of a different type, the printed circuit board may need to be modified to accommodate its pinout and dimensions.

Setting up is a painstaking task and comes down to calibrating the resistor scale R 3.

Karavkin V.

The day off has arrived. Since there were no plans, I decided to assemble some kind of structure. Having scoured the Internet, I didn’t find anything interesting for myself. I decided to come up with my own. Without thinking twice I came up with simple timer. It consists of 2 parts. The first part is a timing circuit, and the second is a transistor switch with a load connected to it.

Timer circuit

The circuit works as follows: when you press the button, capacitor C1 is charged through resistor R3. When the capacitor is charged, transistor VT1 opens. It amplifies transistor VT2, through which the load current will flow. But capacitor C1 is discharged through resistors R1 and R2. The lower the value of resistor R1, the faster the capacitor will discharge. Resistor R2 is installed so that after charging the capacitor, the capacitor does not discharge instantly. Thus, we increase the life of the capacitor.

I decided to assemble the circuit on a one-sided PCB 25mm long and 20mm wide. I drew the paths on the board with a permanent marker and painted over the top with paint. Poisoned in ferric chloride about forty minutes. I washed off the paint with a solvent and then tinned the board.

Now let's start soldering. First of all, we solder the transistors, since they have short legs, and therefore it is more difficult to solder. Then we solder the capacitor. Then all the resistors, followed by the LED, after the wires and the terminal block. If everything is soldered correctly, the circuit will work immediately.

Transistors can be replaced with any n-p-n structures. If you connect a load whose current is higher than 50mA, then I advise you to replace the KT315 transistor with a more powerful one. Resistor R3 can be replaced with any other one with a resistance of 200-1000 Ohms.

Resistor R2 can be replaced with any other one with a resistance of 50-1000 Ohms. Resistor R1 can be replaced with a constant one if time adjustment is not required. Resistor R5 can be replaced with another one with a resistance of 7.5-12.5 kOhm. It is better to leave resistors R6 and R7 unchanged. The capacitor can be replaced with another capacitance. But its tension cannot be reduced.

To make the timer work more clearly, I decided to assemble a simple tweeter. I didn’t etch the board, I collected everything on cardboard. A 50 ohm speaker is connected to this circuit, which can be taken from the handsets of Soviet telephones. You can place a button with the same capacitor in parallel with the capacitor, and when you press the button, the sound from the speaker will sound several tones lower.

I would like to remind you that in parallel with the diode you can turn on an electromagnetic relay with a winding current of no more than 50 mA (if you have KT315). And now a short video about the operation of the device:

With the ratings indicated in the diagram, the delay time is not long, but it can easily be increased by installing a capacitance of a larger rating. I assembled the circuit bkmz268.

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