Adjustable timer on ne555. Detailed description, application and circuits for switching on the NE555 timer. Option #2: Chip-based

It is possible to activate and deactivate household appliances without the presence and participation of the user. Most of the models produced today are equipped with a timer for automatic start / stop.

What to do if you want to manage outdated equipment in the same way? Stock up on patience, our advice and make a time relay with your own hands - believe me, this homemade product will be used in the household.

We are ready to help you realize an interesting idea and try your hand at the path of an independent electrical engineer. For you, we have found and systematized all the valuable information about the options and methods for manufacturing relays. The use of the information provided guarantees easy assembly and excellent performance of the instrument.

In the article proposed for study, home-made versions of the device tested in practice are analyzed in detail. The information is based on the experience of enthusiastic electrical craftsmen and the requirements of regulations.

Man has always sought to make his life easier by introducing various devices into everyday life. With the advent of technology based on an electric motor, the question arose of equipping it with a timer that would automatically control this equipment.

Turned on for a specified time - and you can go do other things. The unit will turn itself off after the set period. For such automation, a relay with an auto-timer function was required.

A classic example of the device in question is in a relay in an old Soviet-style washing machine. On its body there was a pen with several divisions. I set the desired mode, and the drum spins for 5-10 minutes, until the clock inside reaches zero.

The electromagnetic time switch is small in size, consumes little electricity, has no broken moving parts and is durable

Today they are installed in various equipment:

microwave ovens, ovens and other household appliances;
exhaust fans;
automatic watering systems;
lighting control automation.

In most cases, the device is made on the basis of a microcontroller, which simultaneously controls all other modes of operation of automated equipment. It's cheaper for the manufacturer. No need to spend money on several separate devices responsible for one thing.

According to the type of element at the output, the time relay is classified into three types:

relay - the load is connected through a "dry contact";
triac;
thyristor.

The first option is the most reliable and resistant to surges in the network. A device with a switching thyristor at the output should be taken only if the connected load is insensitive to the shape of the supply voltage.

To make a time relay yourself, you can also use a microcontroller. However, homemade products are mainly made for simple things and working conditions. An expensive programmable controller in such a situation is a waste of money.

There are much simpler and cheaper circuits based on transistors and capacitors. Moreover, there are several options, there are plenty to choose from for your specific needs.

Schemes of various homemade products

All the proposed do-it-yourself manufacturing options for time relays are built on the principle of starting a set shutter speed. First, a timer is started with a specified time interval and a countdown.

The external device connected to it starts working - the electric motor or the light turns on. And then, upon reaching zero, the relay gives a signal to turn off this load or block the current.

Option # 1: the easiest on transistors

Transistor-based circuits are the easiest to implement. The simplest of them includes only eight elements. To connect them, you don’t even need a board, everything can be soldered without it. A similar relay is often made to connect lighting through it. I pressed the button - and the light is on for a couple of minutes, and then turns itself off.

To power this circuit, 9 or 12 volt batteries are required, and such a relay can also be powered from 220 V variables using a 12 V DC converter (+)

To assemble this homemade time relay, you will need:

a pair of resistors (100 Ohm and 2.2 mOhm);
bipolar transistor KT937A (or analogue);
load switching relay;
820 ohm variable resistor (for adjusting the time interval);
capacitor at 3300 uF and 25 V;
rectifier diode KD105B;
switch to start the countdown.

The time delay in this relay-timer occurs due to the charging of the capacitor to the power level of the transistor key. While C1 is charging to 9-12 V, the key in VT1 remains open. External load is powered (light on).

After some time, which depends on the value set on R1, the transistor VT1 closes. Relay K1 eventually de-energizes and the load is de-energized.

The charge time of the capacitor C1 is determined by the product of its capacitance and the total resistance of the charging circuit (R1 and R2). Moreover, the first of these resistances is fixed, and the second is adjustable to set a specific interval.

The timing parameters for the assembled relay are selected empirically by setting different values on R1. To later make it easier to set the desired time, markings with minute-by-minute positioning should be made on the case.

It is problematic to specify the formula for calculating the issued delays for such a scheme. Much depends on the parameters of a particular transistor and other elements.

Bringing the relay to its original position is performed by reverse switching S1. The capacitor closes on R2 and discharges. After switching on S1 again, the cycle starts anew.

In a circuit with two transistors, the first one is involved in the regulation and control of the time pause. And the second is an electronic key for turning on and off the power of an external load.

The most difficult thing in this modification is to accurately select the resistance R3. It should be such that the relay closes only when a signal is applied from B2. In this case, the reverse switching on of the load must occur only when B1 is triggered. It will have to be selected experimentally.

This type of transistor has a very low gate current. If the resistance winding in the control relay-key is selected large (tens of ohms and MΩ), then the shutdown interval can be increased to several hours. Moreover, most of the time, the relay-timer practically does not consume energy.

The active mode in it begins in the last third of this interval. If the RV is connected through a conventional battery, then it will last a very long time.

Option #2: Chip-based

Transistor circuits have two main disadvantages. For them, it is difficult to calculate the delay time and before the next start it is required to discharge the capacitor. The use of microcircuits eliminates these shortcomings, but complicates the device.

However, if you have even minimal skills and knowledge in electrical engineering, making such a time relay with your own hands is also not difficult.

The opening threshold of the TL431 is more stable due to the presence of a reference voltage source inside. Plus, it requires a much higher voltage to switch it. At the maximum, by increasing the value of R2, it can be raised to 30 V.

The capacitor will take a long time to charge to such values. In addition, connecting C1 to the resistance for discharging in this case occurs automatically. Additionally, you do not need to click on SB1 here.

Another option is to use the "integral timer" NE555. In this case, the delay is also determined by the parameters of the two resistors (R2 and R4) and the capacitor (C1).

“Turning off” the relay occurs due to the switching again of the transistor. Only its closure here is performed by a signal from the output of the microcircuit, when it counts the necessary seconds.

There are much fewer false positives when using microcircuits than when using transistors. The currents in this case are more tightly controlled, the transistor opens and closes exactly when required.

Another classic microcircuit version of the time relay is based on the KR512PS10. In this case, when the power is turned on, the R1C1 circuit supplies a reset pulse to the input of the microcircuit, after which the internal generator starts in it. The shutdown frequency (division ratio) of the latter is set by the control circuit R2C2.

The number of pulses to be counted is determined by switching the five outputs M01-M05 in various combinations. The delay time can be set from 3 seconds to 30 hours.

After counting the specified number of pulses, the output of the Q1 chip is set to a high level, which opens VT1. As a result, relay K1 is activated and turns the load on or off.

The assembly scheme of the time relay using the KR512PS10 microcircuit is not complicated, resetting to the initial state in such a PB occurs automatically when the specified parameters are reached by connecting the legs 10 (END) and 3 (ST) (+)

There are even more complex time relay circuits based on microcontrollers. However, they are not suitable for self-assembly. There are difficulties with both soldering and programming. Variations with transistors and the simplest microcircuits for domestic use are enough in the vast majority of cases.

Option #3: powered by 220V output

All of the above circuits are designed for a 12-volt output voltage. To connect a powerful load to a time relay assembled on their basis, it is necessary at the output. To control electric motors or other complex electrical equipment with increased power, you will have to do this.

However, to adjust household lighting, you can assemble a relay based on a diode bridge and a thyristor. At the same time, it is not recommended to connect anything else through such a timer. The thyristor passes through itself only the positive part of the sine wave of 220 Volt variables.

For an incandescent bulb, a fan or a heating element, this is not scary, and other electrical equipment of this kind may not withstand and burn out.

The time relay circuit with a thyristor at the output and a diode bridge at the input is designed to operate in 220 V networks, but has a number of restrictions on the type of connected load (+)

To assemble such a timer for a light bulb, you need:

constant resistance at 4.3 MΩ (R1) and 200 Ω (R2) plus adjustable at 1.5 kΩ (R3);
four diodes with a maximum current above 1 A and a reverse voltage of 400 V;
0.47 uF capacitor;
thyristor VT151 or similar;
switch.

This relay-timer functions according to the general scheme for such devices, with the gradual charging of the capacitor. When the contacts are closed on S1, C1 starts charging.

During this process thyristor VS1 remains open. As a result, a mains voltage of 220 V is supplied to the load L1. After charging C1, the thyristor closes and cuts off the current, turning off the lamp.

The delay is adjusted by setting the value on R3 and selecting the capacitance of the capacitor. At the same time, it must be remembered that any touch to the bare legs of all used elements threatens with electric shock. They are all powered by 220V.

If you don’t want to experiment and assemble the time relay yourself, you can pick up ready-made options for switches and sockets with a timer.

More information about such devices is written in the articles:

Conclusions and useful video on the topic

Understanding the internals of a time relay from scratch is often difficult. Some lack knowledge, while others lack experience. To make it easier for you to choose the right circuit, we have made a selection of videos that describe in detail all the nuances of the operation and assembly of the electronic device in question.

If you need a simple device, then it is better to take a transistor circuit. But to accurately control the delay time, you will have to solder one of the options on a particular microcircuit.

If you have experience in assembling such a device, please share the information with our readers. Leave comments, attach photos of your homemade products and participate in discussions. The contact block is located below.

In this article I will tell you how to make a simple timer on the NE 555P chip, in the assembly of which a kit kit will help us, which can be ordered from the link at the end of the article. On the basis of this kit-set, you can make, for example, a flasher or the periodic inclusion of a device.

This kit kit is suitable for beginner radio amateurs to learn how to work with a soldering iron, as it does not require special skills.

Before moving on to reading the article, I suggest watching a video with the complete assembly process, as well as checking the finished kit kit.

In order to make a timer on the NE 555P, you will need:
* Kit set
* Soldering iron, solder, flux
* Side cutters
* Device for soldering "third hand"
* Flat head screwdriver
* Power supply to check the finished device

Step one.
To begin with, consider the delivery kit of the radio designer.

In the kit we have a printed circuit board, it is made quite well and has contacts on both sides with all the signed components, so as not to be mistaken, since there are no instructions for the radio designer.

The timer is based on the NE 555P chip, and the kit also has two variable resistors to adjust the timer operation time.

The timer has connectors on its board, with the help of which, by rearranging the jumper, capacitors of different capacities will change, which will affect the timer operation time.

Step two.
First of all, we install the board in a special "third hand" soldering clamp.

We begin to arrange the components. We have only one resistor in the kit, so you do not need to measure its nominal resistance.

If necessary, the resistance can be measured with a multimeter or color marking on the case.
Step three.
We install non-polar ceramic capacitors, there is a number on their case, they are also indicated on the board.

We insert the components and bend their leads so that they do not fall out during soldering.

Next, we insert polar capacitors, we have three of them in the circuit and have different capacities. A white strip is applied to their case, opposite it is a negative terminal, plus a capacitor is a long leg. On the board, the minus is indicated by hatching, we insert the capacitors according to the ratings on the case and the board.

Step four.
Now let's install the heart of the timer, namely the NE 555P chip, install it according to the key on the case, made in the form of a round recess, which is repeated on the printed circuit board marking.

We put the red LED in its place, its long leg is a plus, a short minus. On the board, a dash is a negative contact, a triangle is a positive one. Next, we insert two variable resistors and outputs for connecting power and jumpers to change the timer operation time.

Step five.
All components on the board are installed. We apply flux for better soldering and solder the leads to the board contacts.

After soldering, remove the remnants of the leads using side cutters. When biting off the leads with side cutters, be careful, as you can accidentally remove the track from the board.

Step six.
It's time to test the timer. We connect the power supply to the contacts on the board and set the jumper to any of the four positions. The LED blinks, which means the kit is working, the response time can be changed with a screwdriver, by turning the screw of the variable resistors, and also by moving the jumper to another position, thereby switching the capacitance depending on the connected capacitor.

Every radio amateur has met with the NE555 chip more than once. This little eight-legged timer has gained enormous popularity for its functionality, practicality and ease of use. On the 555 timer, you can assemble circuits of various levels of complexity: from a simple Schmitt trigger, with a body kit of just a couple of elements, to a multi-stage combination lock using a large number of additional components.

In this article, we will take a closer look at the NE555 chip, which, despite its advanced age, is still in demand. It should be noted that, first of all, this demand is due to the use of ICs in circuitry using LEDs.

Description and scope

NE555 is the development of the American company Signetics, whose specialists did not give up in the conditions of the economic crisis and were able to bring to life the works of Hans Camenzind. It was he who in 1970 managed to prove the importance of his invention, which at that time had no analogues. The NE555 IC had a high mounting density at a low cost, which earned it a special status.

Subsequently, competing manufacturers from around the world began to copy it. This is how the domestic KR1006VI1 appeared, which remained unique in this family. The fact is that in KR1006VI1 the stop input (6) has priority over the start input (2). In imported analogues of other firms, this feature is absent. This fact should be taken into account when developing circuits with the active use of two inputs.

However, in most cases, priorities do not affect the operation of the device. In order to reduce power consumption, back in the 70s of the last century, the production of a CMOS timer was launched. In Russia, the field-effect transistor microcircuit was named KR1441VI1.

The 555 timer found its greatest application in the construction of generator circuits and time relays with the possibility of delays from microseconds to several hours. In more complex devices, it performs the functions of eliminating contact bounce, PWM, restoring a digital signal, and so on.

Features and disadvantages

A feature of the timer is an internal voltage divider that sets a fixed upper and lower threshold for two comparators. Since the voltage divider cannot be eliminated and the threshold voltage cannot be controlled, the scope of the NE555 is narrowed.

Timers assembled on CMOS transistors do not have these disadvantages and do not need to install external capacitors.

The main parameters of the IC series 555

The internal structure of the NE555 includes five functional nodes, which can be seen in the logic diagram. A resistive voltage divider is located at the input, which forms two reference voltages for precision comparators. The output contacts of the comparators go to the next block - an RS flip-flop with an external reset pin, and then to the power amplifier. The last node is an open collector transistor, which can perform several functions, depending on the task.

The recommended supply voltage for IC types NA, NE, SA is in the range from 4.5 to 16 volts, and for SE it can reach 18V. In this case, the current consumption at the minimum Upit is 2–5 mA, at the maximum Upit it is 10–15 mA. Some 555 CMOS ICs draw as little as 1 mA. The largest output current of the imported microcircuit can reach 200 mA. For KR1006VI1, it is not higher than 100 mA.

Build quality and manufacturer greatly affect the operating conditions of the timer. For example, the operating temperature range of NE555 is 0 to 70°C and SE555 is -55 to +125°C, which is important to know when designing devices for outdoor environments. You can get acquainted with the electrical parameters in more detail, find out the typical values of voltage and current at the CONT, RESET, THRES, and TRIG inputs in the datasheet on the XX555 series ICs.

Location and purpose of pins

The NE555 and its counterparts are predominantly available in 8-pin PDIP8, TSSOP, or SOIC packages. The layout of the pins, regardless of the case, is standard. The conventional graphic designation of the timer is a rectangle labeled G1 (for a single pulse generator) and GN (for multivibrators).

Common (GND). The first conclusion is regarding the key. Connects to the negative power of the device.
Trigger (TRIG). Applying a low-level pulse to the input of the second comparator leads to the launch and the appearance of a high-level signal at the output, the duration of which depends on the value of the external elements R and C. Possible variations of the input signal are described in the "Single vibrator" section.
Output (OUT). The high level of the output signal is (Upit-1.5V), and the low level is about 0.25V. Switching takes about 0.1 µs.
Reset (RESET). This input has the highest priority and is able to control the operation of the timer regardless of the voltage on the other outputs. To enable the launch, it is necessary that a potential of more than 0.7 volts be present on it. For this reason, it is connected through a resistor to the power supply of the circuit. The appearance of a pulse less than 0.7 volts disables the operation of the NE555.
Control (CTRL). As can be seen from the internal structure of the IC, it is directly connected to the voltage divider and, in the absence of external influence, gives out 2/3 Upit. By applying a control signal to CTRL, you can get a modulated signal at the output. In simple circuits, it is connected to an external capacitor.
Stop (THR). It is the input of the first comparator, the appearance on which a voltage of more than 2/3Upit stops the trigger and sets the timer output to a low level. In this case, there should be no trigger signal at pin 2, since TRIG has priority over THR (except for KR1006VI1).
Discharge (DIS). Connected directly to the internal transistor, which is connected in a common collector circuit. Typically, a timing capacitor is connected to the collector-emitter junction, which discharges while the transistor is in the on state. Less commonly used to increase the load capacity of the timer.
Power supply (VCC). It is connected to the plus of the 4.5-16V power supply.

NE555 operating modes

The 555 series timer operates in one of three modes, we will consider them in more detail using the NE555 microcircuit as an example.

single vibrator

The circuit diagram of the single vibrator is shown in the figure. To form single pulses, in addition to the NE555 microcircuit, you will need a resistance and a polar capacitor. The scheme works as follows. A single low-level pulse is applied to the input of the timer (2), which leads to the switching of the microcircuit and the appearance of a high signal level at the output (3). Signal duration is calculated in seconds using the formula:

After the specified time (t) has elapsed, a low-level signal is generated at the output (initial state). By default, pin 4 is combined with pin 8, that is, it has a high potential.

During the development of schemes, you need to take into account 2 nuances:

The power supply voltage does not affect the duration of the pulses. The higher the supply voltage, the higher the charge rate of the timing capacitor and the greater the amplitude of the output signal.
An additional pulse that can be applied to the input after the main one will not affect the operation of the timer until the time t expires.

The operation of the single pulse generator can be influenced from the outside in two ways:

send a low-level signal to Reset, which will reset the timer to its original state;
as long as input 2 is low, the output will remain high.

Thus, with the help of single signals at the input and the parameters of the timing chain, it is possible to obtain rectangular pulses with a clearly defined duration at the output.

multivibrator

The multivibrator is a generator of periodic rectangular pulses with a given amplitude, duration or frequency, depending on the task. Its difference from a single vibrator is the absence of an external disturbing influence for the normal functioning of the device. A schematic diagram of a multivibrator based on the NE555 is shown in the figure.

Resistors R 1, R 2 and capacitor C 1 are involved in the formation of repetitive pulses. Pulse time (t 1), pause time (t 2), period (T) and frequency (f) are calculated using the formulas below: From these formulas, it is easy to see that the pause time cannot exceed the pulse time, that is, it will not be possible to achieve a duty cycle (S \u003d T / t 1) of more than 2 units. To solve the problem, a diode is added to the circuit, the cathode of which is connected to pin 6, and the anode to pin 7.

In the datasheet for microcircuits, they often operate with the reciprocal of the duty cycle - Duty cycle (D \u003d 1 / S), which is displayed as a percentage.

The scheme works as follows. At the time of power-up, capacitor C 1 is discharged, which puts the timer output in a high level state. Then C 1 starts charging, gaining capacity up to the upper threshold value 2/3 U PIT. Having reached the threshold, the IC switches, and a low signal level appears at the output. The process of discharging the capacitor (t 1) begins, which continues until the lower threshold value 1/3 U PIT. Upon reaching it, the reverse switching occurs, and a high signal level is set at the output of the timer. As a result, the circuit goes into self-oscillating mode.

Precision Schmitt Trigger with RS Trigger

Inside the NE555 timer, a two-prog comparator and an RS flip-flop are built-in, which allows you to implement a precision Schmitt trigger with an RS flip-flop in hardware. The input voltage is divided by the comparator into three parts, upon reaching each of which the next switching occurs. In this case, the value of hysteresis (reverse switching) is equal to 1/3 U PIT. The possibility of using NE555 as a precision trigger is in demand in the construction of automatic control systems.

3 most popular circuits based on NE555

single vibrator

A practical version of the TTL NE555 single vibrator circuit is shown in the figure. The circuit is powered by a unipolar voltage from 5 to 15V. The time-setting elements here are: resistor R 1 - 200 kOhm-0.125 W and electrolytic capacitor C 1 - 4.7 μF-16V. R 2 maintains a high potential at the input until some external device resets it to a low level (for example, a transistor switch). Capacitor C 2 protects the circuit from through currents at the moments of switching.

The activation of a single vibrator occurs at the moment of a short-term short circuit to the ground of the input contact. In this case, a high level is formed at the output with a duration of:

t \u003d 1.1 * R 1 * C 1 \u003d 1.1 * 200000 * 0.0000047 \u003d 1.03 s.

Thus, this circuit generates a delay of the output signal relative to the input signal by 1 second.

Flashing LED on multivibrator

Based on the multivibrator circuit discussed above, you can assemble a simple LED flasher. To do this, an LED is connected in series with the resistor to the output of the timer. The value of the resistor is found by the formula:

R=(U OUT -U LED)/I LED ,

U OUT - the amplitude value of the voltage at pin 3 of the timer.

The number of connected LEDs depends on the type of NE555 chip used, its load capacity (CMOS or TTL). If it is necessary to blink an LED with a power of more than 0.5 W, then the circuit is supplemented with a transistor, the load of which will be the LED.

Time relay

The scheme of the adjustable timer (electronic time relay) is shown in the figure.
With its help, you can manually set the duration of the output signal from 1 to 25 seconds. To do this, in series with a fixed resistor of 10 kΩ, a variable value of 250 kΩ is installed. The capacitance of the timing capacitor is increased to 100 uF.

The scheme works as follows. In the initial state, pin 2 is high (from the power supply), and pin 3 is low. Transistors VT1, VT2 are closed. At the moment a positive pulse is applied to the base VT1, a current flows through the circuit (Vcc-R2-collector-emitter-common wire). VT1 opens and puts the NE555 into timing mode. At the same time, a positive pulse appears at the output of the IC, which opens VT2. As a result, the emitter current VT2 leads to the operation of the relay. The user can interrupt the execution of the task at any time by briefly shorting RESET to ground.

The SS8050 transistors shown in the diagram can be replaced with KT3102.

It is impossible to review all popular circuits based on NE555 in one article. For this, there are entire collections, which contain practical developments for the entire time of the existence of the timer. We hope that the information provided will serve as a guide during the assembly of circuits, including the load of which are LEDs.

A simple timer on the NE555 chip

If necessary, the circuit can be powered by a 12 volt battery. This battery is shown in the diagram (BATT.1). With switch S2, you can select the power source for the timer - a battery or a rectifier. if battery power is not required, BATT.1 and S2 are not needed.

Device basis- integrated timer chip type NE555, configured to operate in monostable mode. The scheme provides working out of time intervals in the range from 1 to 30 minutes. The desired time is selected by switch S1 in accordance with the table:

The "START" button (S1) is used to start the timing process. When this button is pressed, the electromagnetic relay RL1 will work and connect the load to the 220v network. After a specified period of time, the relay will release and open the load power circuit.

Circuit operation very simple. Capacitor C1 is infected through a resistor or a chain of resistors R1 - R6. At the moment the "START" button (S3) is pressed, the timer turns on and a high voltage level appears at its output (3). The high voltage level at the output of the microcircuit remains high for the time selected by switch S1. A high voltage level at the output of microcircuit 555 opens the transistor T1, in the collector circuit of which the winding of the electromagnetic relay RL1 is included. The relay is activated, its contacts close and turn on the load in the 220 volt network.

Throughout our life, we count the intervals of time that determine certain events of our existence one after another. In general, we cannot do without counting time in our lives, because in fact we distribute our daily routine by hours and minutes, and these days add up to weeks, months and years. It can be said that without time we would lose some definite meaning in our actions, and even more literally, chaos would definitely break into our lives. But in this article we are not at all about the fantastic realities of the probable and not even about the hypothetically improbable, but nevertheless about the really accessible. After all, if we need this, if something to which we have become accustomed is so necessary, then why give up the convenient!? We are talking about how and with what it is time to measure. No, this slogan about how you can measure time is somewhat amusing, as even a first grader knows this. Take an ordinary watch of any possible design, be it mechanical, sand, electronic, and measure time. However, watches may not always be comfortable. Let's say if we need to start or turn off some kind of electronic design, then it is best to implement this on an electronic timer. It is he who will take over the debts for turning the device on and off, by means of automatic electronic switching of control structures. It is about such a timer on the NE 555 chip that we will describe in our article.

Timer circuit on the NE555 chip

Take a look at the drawing. As trite as it may seem, the NE555 chip in this circuit actually operates in its normal mode, that is, for its intended purpose. Although in fact it can be used as a multivibrator, as a converter of an analog signal to digital, as a microcircuit providing a load table from a light sensor.

Let's briefly go over again the connection of the microcircuit and the principle of the work of the circuit.

After pressing the "reset" button, we reset the potential at the input of the microcircuit, since we essentially ground the input. In this case, the 150 uF capacitor is discharged. Now, depending on the capacitance connected to the 6.7 leg and the ground (150 uF), the timer delay-hold stage will depend. Note that a number of 500 kΩ and 2.2 mΩ resistors are also connected here, so these resistors are also involved in the formation of the delay-exposure. You can adjust the delay with the support of a variable resistor of 2.2 M. But the most effective time can be changed by changing the capacitor line. So with a resistance of a chain of resistors of about 1 mOhm, the delay will be about 5 minutes. Accordingly, if you unscrew the resistor to the maximum and make sure that the capacitor charges as slowly as possible, then you can achieve a delay of 10 minutes. Here it is necessary to say that at the start of the countdown of the timer, the green LED lights up, when the timer is triggered, then the output is negative potential and because of this the green LED goes out and the scarlet one lights up. That is, depending on what you need, a timer to turn on or off, you can use the appropriate connection, to a red or green LED. The scheme is simple and with the correct connection of all elements in the setting, it does not live in misery.

P / S When I found this circuit on the Internet, it also had a connection between pin 2 and 4, but with such a connection, the circuit does not work !!! Pin 2 must be connected to pin 6, this conclusion was made based on other similar schemes on the Internet. With this connection, everything worked!!!

If you need to control the timer with a power load, you can use the signal after the 330 ohm resistor. This point is shown by a scarlet and green cross. We use a conventional transistor, say KT815 and a relay. The relay can be used for 12 volts. An example of such a power management implementation is given in the light sensor article, see the link longer. In this case, it will be possible to turn off and on a powerful load.

Summing up the timer on the NE555 chip

The circuit shown here, although it operates from 9 volts, can also be powered by 12 volts. This means that such a circuit can be used not only for home projects, but also for a car, when the circuit can be directly connected to the vehicle's on-board network.
In this case, such a timer can be used to delay turning the camera on or off. It is possible to use a timer for "lazy" turn indicators, for heating the rear window, etc. There are really many options.