Why relay driver is used

In Market Relay module can purchased by telling how many Channel Relay is Required and operating voltage. Advantage: You will be able to control various appliances, and other equipments with large current. It can be controlled directly by Microcontroller.

Here is Picture of some common Relay Driver Module available in the market. Electronics Students uses it with Arduino and other microprocessor Projects etc.

Download Now Download to read offline and view in fullscreen. Download Now Download Download to read offline. Relay driver Download Now Download Download to read offline. Syed Ghufran Hassan Follow. Drink and Drive Alcohol Detection. Microcontroller based automatic engine locking system for drunken drivers.

Interfacing Stepper motor with Stepper Motor Control System. Gsm based home automation. Microcontroller in automobile and applications. Safe driving with alcohol detection ppt. Related Books Free with a 30 day trial from Scribd. Elsevier Books Reference. Germany, September Elsevier Books Reference. Related Audiobooks Free with a 30 day trial from Scribd. Shubham Srivastava. Vivek Krishna. Views Total views. Actions Shares. No notes for slide. Relay driver 1. What is relay?

A relay is electro mechanical switch which is used in industrial application to provide isolation between high voltage and low voltage circuits. These two circuits have different voltage rating. One might be a low voltage side and other high voltage side. For example, in microcontrollers based circuits, relay is used to isolate microcontrollers from volt AC supply. Components of electro mechanical relay? Electrical mechanical relay have three main components: 1. Coil 2. When coil is energize with 5 volt signal, current flows through the coil.

When current flows through the coil, a magnetic field is created in the coil which attract causes the armature contacts to attract towards spring. When no current flows through coil, spring causes the contacts to pull towards normal position. Circuit diagram of electro mechanical relay with components are given below: how to use relay In above circuit diagram 5 volt signal is given to coil of electro mechanical relay, when switch is closed, current flows through the coil and energize the coil.

When coil energize through 5 volt signal, spring attracts contact form normally open position to closed position. On Left hand side of coil is normally open position of contact. Because circuit is no complete or in other words current flow path is not complete. When coil is energized with the help of 5 volt signal, internal spring of electro mechanical relay attract or pulls contact towards other point and complete the circuit. A electro mechanical relay can be either normally open or normally closed.

In above circuit diagram, Normally open electro mechanical relay is used. A voltage required to energize the coil, vary from relay to relay. Voltage may vary from 5 volt to 50 volt and current may very from mA to 20mA. The relays also have minimum voltage rating. Its means below voltage rating relay will not operate. One can check minimum operating voltage o relay in its data sheet. But current requirements are not specified in date sheets. It is also possible to create a GenStart Trigger from other variables such as Load Current for large DC loads to prevent the battery from getting discharged.

However, there is just a single GenStart Setting so the only way to add additional triggers is by using Boolean Logic with additional RD-1 channels or other external switches. Relay Driver Overview and Applications. Figure 2: Voltage Measuring Diagram.

Figure 3: Simple Advanced Setup Selection. Figure 4: Channel Function Selection. Figure 5: Control Type Device Selection. Figure 6: Relay Driver Boolean Logic. Figure 9: Threshold Setup. Figure GenStart Signals. Figure Run Timer 2-wire setup.

Figure Simple 3-Wire GenStart. Figure GenStart Trigger Settings. I will also discuss other methods of relay driver circuits in the later part of this article.

While working on electronics projects which used a microcontroller, we need to use relays to control AC loads or high voltage loads. Therefore relay driver circuits IC is used to derive relays properly. There are many ways to design relay driver circuits. But dedicated relay driver circuits integrated circuits are available which serve the purpose of relay driver IC. The relay driver circuit using an NPN transistor is given below.

Transistor is used as a switch in this circuit. The microcontroller provides High or low input signals to NPN transistors. NPN transistor provides high driving current to electromechanical relay through the volt external power supply.

Following components are used in relay driver circuit using transistor:. ULN is a very famous relay driver integrated circuit. Its contains seven Darlington pair of a transistor which have high voltage and high current carrying capability. Its mean ULN can drive up to seven relays at a time. A diode is used with each pair of NPN Darlington transistor. Diode makes it easily useable with inductive loads.

There are many applications of a relay driver circuit using uln, but some of the famous applications are given below:. The relay driver circuit using uln is given below. In this circuit diagram, the pic microcontroller is providing a signal to 4 relays through relay driver IC uln Single ULN can be easily used int this circuit to drive up to five relays.