Generator based on NE555 timer. Generator based on NE555 timer How to increase output power

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The proposed sine wave test audio generator is based on a Wien bridge, produces very low sine wave distortion and operates from 15 Hz to 22 kHz in two sub-bands. Two levels of output voltages - from 0-250 mV and 0-2.5 V. The circuit is not at all complicated and is recommended for assembly even by inexperienced radio amateurs.

Audio Generator Parts List

  • R1, R3, R4 = 330 Ohm
  • R2 = 33 Ohm
  • R5 = 50k dual potentiometer (linear)
  • R6 = 4.7k
  • R7 = 47k
  • R8 = 5k potentiometer (linear)
  • C1, C3 = 0.022uF
  • C2, C4 = 0.22uF
  • C5, C6 = 47uF electrolytic capacitors (50v)
  • IC1 = TL082 double op-amp with socket
  • L1 = 28V/40mA lamp
  • J1 = BNC connector
  • J2 = RCA Jack
  • B1, B2 = 9 V Krona


The circuit laid out above is quite simple, and is based on a dual operational amplifier TL082, which is used as an oscillator and buffer amplifier. Industrial analog generators are also built approximately according to this type. The output signal is sufficient even to connect 8 ohm headphones. In standby mode, the current consumption is about 5 mA from each battery. There are two of them, 9 volts each, since the op-amp power supply is bipolar. Two different types of output connectors are installed for convenience. For super-bright LEDs, you can use 4.7k resistors R6. For standard LEDs - 1k resistor.


The oscillogram shows the actual 1 kHz output signal from the generator.

Generator assembly

The LED serves as an on/off indicator for the device. Regarding the L1 incandescent bulb, many types of bulbs were tested during the assembly process and all worked well. Start by cutting the PCB to the desired size, etching, drilling and assembly.


The body here is half-wooden - half-metal. Cut two inch-thick pieces of wood for the sides of the cabinet. Cut a piece of 2mm aluminum plate for the front panel. And a piece of white matte cardboard for the scale dial. Bend two pieces of aluminum to form battery holders and screw them to the sides.

The inverter consists of a master oscillator of 50 Hertz (up to 100 Hz), which is built on the basis of the most common multivibrator. Since the publication of the scheme, I have observed that many have successfully repeated the scheme, the reviews are quite good - the project was a success.

This circuit allows you to get almost mains 220 Volts with a frequency of 50 Hz at the output (depending on the frequency of the multivibrator. The output of our inverter is rectangular pulses, but please do not rush to conclusions - such an inverter is suitable for powering almost all household loads, with the exception of those loads that have built-in motor that is sensitive to the shape of the supplied signal.

TV, players, chargers for laptops, laptops, mobile devices, soldering irons, incandescent lamps, LED lamps, LDS, even a personal computer - all this can be powered without any problems from the proposed inverter.

A few words about the power of the inverter. If you use one pair of power switches of the IRFZ44 series with a power of about 150 watts, the output power is indicated below depending on the number of pairs of keys and their type

Transistor Number of pairs Power, W)
IRFZ44/46/48 1/2/3/4/5 250/400/600/800/1000
IRF3205/IRL3705/IRL 2505 1/2/3/4/5 300/500/700/900/1150
IRF1404 1/2/3/4/5 400/650/900/1200/1500Max

But that’s not all, one of those people who assembled this device wrote with pride that he managed to remove up to 2000 watts, of course, and this is real if you use, say, 6 pairs of IRF1404 - really killer keys with a current of 202 Amperes, but of course the maximum the current cannot reach such values, since the terminals would simply melt at such currents.

The inverter has a REMOTE function (remote control). The trick is that to start the inverter you need to apply a low-power plus from the battery to the line to which low-power multivibrator resistors are connected. A few words about the resistors themselves - take everything with a power of 0.25 watts - they will not overheat. The transistors in the multivibrator need to be quite powerful if you are going to pump several pairs of power switches. Of ours, KT815/17 or even better KT819 or imported analogues are suitable.

Capacitors are frequency-setting capacitors, their capacity is 4.7 μF; with this arrangement of multivibrator components, the inverter frequency will be around 60 Hz.
I took the transformer from an old uninterruptible power supply, the power of the trance is selected based on the required (calculated) power of the inverter, the primary windings are 2 to 9 Volts (7-12 Volts), the secondary winding is standard - network.
Film capacitors with a rated voltage of 63/160 volts or more, take what you have on hand.

Well, that’s all, I’ll only add that power switches at high power will heat up like a stove, they need a very good heat sink, plus active cooling. Do not forget to isolate the pairs of one arm from the heat sink to avoid short-circuiting of the transistors.


The inverter does not have any protection or stabilization; perhaps the voltage will deviate from 220 Volts.

Download the PCB from the server



Sincerely - AKA KASYAN

The 555 integrated timer chip was developed 44 years ago, in 1971, and is still popular today. Perhaps not a single microcircuit has served people for so long. They collected everything on it, they even say that number 555 is the number of options for its application :) One of the classic applications of the 555 timer is an adjustable rectangular pulse generator.
This review will describe the generator, specific application will be next time.

The board was sent sealed in an antistatic bag, but the microcircuit is very wooden and static cannot easily kill it.


The installation quality is normal, the flux has not been washed off




The generator circuit is standard to obtain a pulse duty cycle of ≤2


The red LED is connected to the output of the generator and blinks at a low output frequency.
According to Chinese tradition, the manufacturer forgot to put a limiting resistor in series with the upper trimmer. According to the specification, it must be at least 1 kOhm so as not to overload the internal switch of the microcircuit, however, in reality the circuit works with lower resistance - up to 200 Ohms, at which generation fails. Adding a limiting resistor to the board is difficult due to the layout of the printed circuit board.
The operating frequency range is selected by installing a jumper in one of four positions
The seller indicated the frequencies incorrectly.


Really measured generator frequencies at a supply voltage of 12V
1 - from 0.5Hz to 50Hz
2 - from 35Hz to 3.5kHz
3 - from 650Hz to 65kHz
4 - from 50kHz to 600kHz

The lower resistor (according to the diagram) sets the pulse pause duration, the upper resistor sets the pulse repetition period.
Supply voltage 4.5-16V, maximum output load - 200mA

The stability of output pulses in ranges 2 and 3 is low due to the use of capacitors made of ferroelectric ceramics of the Y5V type - the frequency creeps away not only when the temperature changes, but even when the supply voltage changes (by several times). I didn’t draw any graphs, just take my word for it.
On other ranges the pulse stability is acceptable.

This is what it produces on range 1
At maximum resistance of trimmers


In meander mode (upper 300 Ohm, lower at maximum)


In maximum frequency mode (upper 300 ohms, lower to minimum)


In the minimum pulse duty cycle mode (upper trimmer at maximum, lower at minimum)

For Chinese manufacturers: add a 300-390 Ohm limiting resistor, replace the 6.8uF ceramic capacitor with a 2.2uF/50V electrolytic capacitor, and replace the 0.1uF Y5V capacitor with a higher quality 47nF X5R (X7R)
Here is the finished modified diagram


I didn’t modify the generator myself, because... These disadvantages are not critical for my application.

Conclusion: the usefulness of the device becomes clear when any of your homemade products require pulses to be sent to it :)
To be continued…

I'm planning to buy +31 Add to favorites I liked the review +28 +58

There is equipment and devices that are not only powered from the electrical network, but also in which the electrical network serves as a source of such impulses necessary for the operation of the device circuit. When such devices are powered from a power supply with a different frequency or from an autonomous source, the problem arises of where to get the clock frequency from.

The clock frequency in such devices is usually either equal to the mains frequency (60 or 50 Hz) or equal to twice the mains frequency, when the source of clock pulses in the device circuit is a circuit based on a bridge rectifier without a smoothing capacitor.

Below are four circuits of pulse generators with frequencies of 50 Hz, 60 Hz, 100 Hz and 120 Hz, built on the basis of the CD4060B microcircuit and a 32768 Hz quartz clock resonator.

50 Hz generator circuit

Rice. 1. Schematic diagram of a signal generator with a frequency of 50 Hz.

Figure 1 shows the circuit of a 50 Hz frequency generator. The frequency is stabilized by quartz resonator Q1 at 32768 Hz; from its output inside the D1 chip, pulses are sent to a binary counter. The frequency division coefficient is set by diodes VD1-VD3 and resistor R1, which reset the counter every time its state reaches 656. In this case, 32768 / 656 = 49.9512195.

It's not quite 50Hz, but it's very close. In addition, by selecting the capacitances of capacitors C1 and C2, you can slightly change the frequency of the quartz oscillator and get a result closer to 50 Hz.

60 Hz generator circuit

Figure 2 shows the circuit of a 60 Hz frequency generator. The frequency is stabilized by quartz resonator Q1 at 32768 Hz; from its output inside the D1 chip, pulses are sent to a binary counter.

Rice. 2. Schematic diagram of a signal generator with a frequency of 60 Hz.

The frequency division coefficient is set by diodes VD1-VD2 and resistor R1, which reset the counter every time its state reaches 544. In this case, 32768 / 544 = 60.2352941. It's not quite 60Hz, but close.

In addition, by selecting the capacitances of capacitors C1 and C2, you can slightly change the frequency of the quartz oscillator and get a result closer to 60 Hz.

100 Hz generator circuit

Figure 3 shows the circuit of a 100 Hz frequency generator. The frequency is stabilized by quartz resonator Q1 at 32768 Hz; from its output inside the D1 chip, pulses are sent to a binary counter. The frequency division coefficient is set by diodes VD1-VD3 and resistor R1, which reset the counter every time its state reaches 328. In this case, 32768 / 328 = 99.902439.

Rice. 3. Schematic diagram of a signal generator with a frequency of 100 Hz.

It's not quite 100 Hz, but close. In addition, by selecting the capacitances of capacitors C1 and C2, you can slightly change the frequency of the quartz oscillator and get a result closer to 100 Hz.

120 Hz generator

Figure 4 shows the circuit of a 120 Hz frequency generator. The frequency is stabilized by quartz resonator Q1 at 32768 Hz; from its output inside the D1 chip, pulses are sent to a binary counter. The frequency division coefficient is set by diodes VD1-VD2 and resistor R1, which reset the counter every time its state reaches 272. In this case, 32768 / 272 = 120.470588.

It's not quite 120Hz, but close. In addition, by selecting the capacitances of capacitors C1 and C2, you can slightly change the frequency of the quartz oscillator and get a result closer to 120 Hz.

Rice. 4. Schematic diagram of a signal generator with a frequency of 120 Hz.

The power supply voltage can be from 3 to 15V, depending on the supply voltage of the circuit, or rather, on the required value of the logic level. The output pulses in all circuits are asymmetrical; this must be taken into account for their specific application.

Pulse former with a period of one minute

Figure 5 shows a circuit of a pulse shaper with a period of one minute, for example, for an electronic digital watch. The input receives a 50 Hz signal from the mains through a transformer, voltage divider or optocoupler, or from another 50 Hz source.

Resistors R1 and R2, together with the inverters of the D1 chip, intended for the clock generator circuit, form a Schmitt trigger, so you don’t have to worry about the shape of the input signal; it can also be a sine wave.

Fig.5. Circuit of a pulse shaper with a period of one minute.

By diodes VD1-VD7, the counter division coefficient is limited to the value 2048+512+256+128+32+16+8=3000, which at an input frequency of 50 Hz at pin 1 of the microcircuit gives pulses with a period of one minute.

Additionally, pulses with a frequency of 0.781 Hz can be removed from pin 4, for example, to set the hour and minute counters to the current time. The power supply voltage can be from 3 to 15V, depending on the supply voltage of the electronic clock circuit, or rather, on the required value of the logic level.

Snegirev I. RK-11-16.

Low Harmonic Test Signal Generator on a Wien Bridge

When you don't have it at hand high quality sine wave generator- how to debug the amplifier you are developing? We have to make do with improvised means.

In this article:

  • High linearity when using a budget op-amp
  • Accurate AGC system with minimal distortion
  • Battery operated: minimal interference

Background

At the beginning of the millennium, our whole family moved to live in distant countries. Some of my electronic supplies followed us, but, alas, not all of them. So I found myself alone with large monoblocks that I had assembled, but not yet debugged, without an oscilloscope, without a signal generator, with a great desire to complete that project and finally listen to music. I managed to get an oscilloscope from a friend for temporary use. With the generator, I urgently had to invent something myself. At that time, I had not yet gotten used to the component suppliers available here. Among the opamps that happened to be at hand were several indigestible products of the ancient Soviet electronics industry, and an LM324 soldered from a burnt computer power supply.
LM324 datasheet: National/TI, Fairchild, OnSemi... I love reading datasheets from National - they usually have a lot of interesting examples of using parts. OnSemi also helped in this case. But “Gypsy Little” deprived its followers of something :)

Classics of the genre

Help the author!

This article showed several simple techniques that allow you to achieve very high-quality generation and amplification of a sinusoidal signal, using a widely available inexpensive operational amplifier and a p-n junction field-effect transistor:

  • Limiting the range of automatic level control and reducing the influence of nonlinearity of the control element;
  • Shifting the op-amp output stage to linear operating mode;
  • Selecting the optimal virtual ground level for battery-powered operation.

Was everything clear? Did you find anything new or original in this article? I will be pleased if you leave a comment or ask a question, and also share the article with your friends on a social network by “clicking” the corresponding icon below.

Addendum (October 2017) Found it on the Internet: http://www.linear.com/solutions/1623. I made two conclusions:

  1. There is nothing new under the sun.
  2. Don't chase after cheap prices, priest! If I had taken a normal op-amp then, I would have gotten an exemplary low Kg.

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