Relay turns on MOSFETs. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Automobile. Electronic devices

Comments on the article

In the proposed turn indicator relay, it was possible to do without a high-current electromagnetic relay with breaking contacts. It is easy to install it in most of both domestic cars and "foreign cars" with a rated voltage of the on-board electrical network of 12 V, instead of failed electronic and simple thermomechanical current breakers.

You see the schematic diagram of the device in Fig. 1, and the drawing of the printed circuit board (dimensions 115x60 mm) - in Fig. 2. All parts of the device, except for the fuse, sound emitter and LED (if desired) are soldered on it.

Fig.1. Schematic diagram of the turn relay (click to enlarge)

Fig.2. Printed circuit board

A pair of modern p-channel MOSFETs of the IRF9540 type is used as a powerful switching node. The resistance of the open source-drain channel of such a transistor does not exceed 0,2 ohms. When two such transistors are connected in parallel, we have a "closed" MOS switch resistance of less than 0,1 Ohm, which gives a voltage drop across it of no more than 1 V at a load current of 10 A. Such remarkable parameters make it possible to use this relay not only to power lamps " turn signals", but also used in the emergency stop signaling system.

To simplify the circuit, a blinking HL1 LED was used as a pulse generator. When the switch SA1 turns on the light signal of the "left" or "right" turn, capacitor C5 is charged through the corresponding diode VD4 or VD2 and current-limiting resistor R2. The emitter follower on VT1 opens, and the LED starts flashing very brightly (the "flash" current is about 6 mA). At the time of the flash, the voltage at HL1 does not exceed 2,2 V, and during a pause it is close to the supply voltage. From the anode of the LED, a rectangular signal, following with a frequency of flashes of light (about 3 Hz), is fed to the input of the SR (pin 2) of a four-digit binary counter DD1. Switching triggers of the counter occurs on the decline of the pulse of positive polarity, i.e. when the LED goes out.

At output 1 (pin 3) of DD1, a rectangular signal appears with a frequency that is half that at the input of the microcircuit. When pin 3 of DD1 is logical "0", the gate-source voltage of field-effect transistors VT3 and VT4 will be about 12 ... 14 V, they are open, and the corresponding lamps will flash.

During the flashes of the lamps, C2 is recharged. At a time when pin 3 DD1 is logic "1", the gate-source voltage VT3, VT4 does not exceed 1 V, the transistors are closed, the lamps do not light.

With every fourth flash of light, a short beep is emitted by the BF1 - a piezoceramic emitter with a built-in generator. This mode is not so annoying during a long stop at a traffic light. In addition, the addictive effect is less when you stop paying attention to the sound signal, and the "turn signals" remain on unnecessarily.

When SA1 opens, the lamps go out, the capacitor C2 quickly discharges through the resistor R1, the LED flashes fade. In rare cases, after opening contacts SA1, it is possible to stop the counter DD1 in such a state when its output 3 is logical "1", transistors VT3, VT4 are closed, and the generator cannot be started on a flashing LED. The R5-VD1-R6-VD2-C3-R4 circuit helps to bring the device out of "hangup". If the logic "1" level is set at output 1, capacitor C1 is charged through VD5 and R3, and (after about 1,5 s) counter DD1 is reset to its initial state when output 1 is logic "0". The R6-VD2 circuit discharges C3 with each flash of the lamps; the voltage on it does not rise above 1,5 V, so the reset input R does not affect the operation of the microcircuit.

A powerful zener diode VD6 with a stabilization voltage of 18 V and the R8-VD3 chain are designed to protect the device from high voltage surges (more than 17 ... 27 V) that slip through the vehicle's on-board electrical network. Capacitor C6 reduces noise from the ignition system.

The volume of control beeps can be adjusted by selecting R9, and their duration depends on the capacity of C5. The repetition period of the beeps can be chosen differently by connecting the top output of R7 according to the diagram to other outputs of DD1.

In this turn relay, you can use any small-sized resistors of types C1-4, C2-23, C2-33, MLT, BC. Reliable and small-sized electrolytic capacitors are desirable, for example, Rubicon, Keltron, Samsung or domestic K52, K53 series. All diodes are silicon, series KD521, KD522, KD105, KD209, etc. Zener diode VD3 is replaced by KS515G, KS508B, KS215Zh, VD6 - by KS541B, KS529A, D816A.

The FU1 fuse can be either a disposable fuse or a self-resetting fuse (MF-R900 9A or more).

It is advisable to take a flashing LED in red, for example, L36BSRD / B, L56BCRD / B, L796BSRD / B, L796BSRC / B, L816BSRD / B with a diameter of 3 to 10 mm from Kingbright. You can use similar LEDs from other companies [4].

Bipolar transistors can install any npn structure with large h_21э from the KT3102, KT315, KT503, KT645 series. In place of VT3, VT4, you can install a pair of powerful p-channel field-effect transistors of the IRF9532, KP784A, KP785A types. It is desirable to place them on small brass or aluminum heat sinks. It should not be forgotten that incandescent lamps have a large starting ignition current. The total pulsed switching current of all lamps should not exceed half of the allowable pulsed current of the field-effect transistors used. If the total power of simultaneously switched on lamps is more than 90 W, it is advisable to install three field-effect transistors in parallel. Chip DD1 can be replaced by KR1561IE10, CD4520AE. Sound emitter with built-in generator can be supplied with EFM-250, EFM-472A, EFM-475, EFM-471L.

Literature

1. A. Butov. Electronic turn signal relay. - Radio, 2002, N8, p.54.
2. P. Golovin. CMOS turn signal relay. - Radio, 1991, N6, S.Z0.
3. A. Ivanov. Direction indicator relay for KR512PS10. - Radio, 1993, N7, p.35.
4. S.Ryumik. All about blinking LEDs... - Radiohobby, 2002, N1, p.31.
5. S. Chebotkov. New powerful field effect transistors. - Radiomir, 2001, N8, p.39.
6. Automotive incandescent lamps. Schematic diagrams of turn signal switches. - Radioamator-Electric, 2002, N7, S. 15.

Author: A.Butov, s.Kurba; Publication: radioradar.net

See other articles Section Automobile. Electronic devices.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive Car tires pollute the world's oceans with microplastics 18.11.2018 Car tires and brake pads produce harmful microplastics that can be found in the air and underwater. The scientists analyzed more than 500 fine particles extracted from the air around three busy German motorways and found that the vast majority - 89 percent of the microparticles - are shed from car tires, brake systems and the roads themselves. Collectively, these particles are classified by researchers as microplastics, although they include materials other than plastic. These particles are blown away by the wind and washed away by rain into waterways leading to the ocean, where they can harm aquatic animals and fragile ecosystems, said environmental scientist Renaud Gier of the University of Pennsylvania and lead author of the study. Previous studies have shown that about 30 percent of the volume of microplastic particles that pollute the oceans, lakes and rivers come from tire wear. "We all want to reduce CO2 emissions from car exhaust," Gier says. "But you can't stop tire wear." Exacerbate traffic congestion. The researchers found that vehicles traveling at a constant speed, without constantly using the brakes, produced fewer harmful particles. Since some materials, including synthetic rubber, get covered in dust and other tougher pieces of debris, they are not always easy to identify. The researchers figured out what each particle was by examining them under a scanning electron microscope and performing chemical analysis.

Other interesting news:

▪ Memory on moving nanotubes

▪ Artificial mother of pearl

▪ tissue that kills viruses

▪ CPU Cooler Zalman CNPS10X Performa Black

▪ Nicotine and Hummingbird

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Digital technology. Article selection

▪ article Materials Science. Lecture notes

▪ article Why can't an ostrich fly? Detailed answer

▪ article Cotoneaster common. Legends, cultivation, methods of application

▪ article Film projector synchronizer - in one day. Encyclopedia of radio electronics and electrical engineering

▪ article Burmese proverbs and sayings. Large selection

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

Home page | Library | Articles | Website map | Site Reviews

www.diagram.com.ua
2000-2024