Relay Interfacing with microcontroller

A relays is an electrical switch that opens and closes under control of another electrical circuit. It is therefore connected to ouput pins of the microcontroller and used to turn on/off high-power devices such as motors, transformers, heaters, bulbs, antenna systems etc. These are almost always placed away from the board sensitive components. There are various types of relays but all of them operate in the same way. When a current flows through the coil, the relay is operated by an electromagnet to open or close one or many sets of contacts. Similar to optocouplers, there is no galvanic connection (electrical contact) between input and output circuits. Relays usually demand both higher voltage and current to start operation, but there are also miniature ones which can be activated by a low current directly obtained from a microcontroller pin.

The figure shows the solution specific to the 8051 microcontroller. A darlington transistor is used here to activate relays because of its high current gain. This is not in accordance with “rules”, but is necessary in the event that logic one activation is applied since the output current is then very low (pin acts as an input).

In order to prevent the appearance of self-induction high voltage, caused by a sudden stop of current flow through the coil, an inverted polarized diode is connected in parallel to the coil. The purpose of this diode is to “cut off” the voltage pea

Tags:relay interfacing with arduino
relay interfacing with 8051 pdf
relay interfacing with lpc2148
relay interfacing with 8051 microcontroller
relay interfacing with 8051 microcontroller pdf
relay interfacing with atmega16
relay interfacing with pic16f877a
relay interfacing with pic microcontroller
relay interfacing with 8051 ppt
relay interfacing with atmega32
relay interfacing with 8051
relay interfacing with arduino
relay interfacing with 8051 pdf
relay interfacing with microcontroller
relay interfacing with lpc2148
relay interfacing with 8051 microcontroller
relay interfacing with 8051 microcontroller pdf
relay interfacing with atmega16
relay interfacing with pic16f877a
relay interfacing with pic microcontroller
interfacing relay atmega32
relay interfacing with atmega16
relay interfacing with arduino
relay interfacing with avr microcontroller
relay interfacing with at89c51
relay interfacing with arm
relay interfacing with at89s52
interfacing a relay with microcontroller
interfacing relay modules to arduino
interfacing a relay to 8051
interfacing a relay with microcontroller
interfacing a relay to 8051
relay interfacing circuit
relay interfacing 8051 circuit
relay interfacing with dc motor
interfacing relay with fpga
relay interfacing in 8051 microcontroller
relay interfacing in proteus
relay interfacing with lpc2148
relay interfacing microcontroller
interfacing relay modules to arduino
relay interfacing with microcontroller pdf
relay interfacing with pic microcontroller
relay interfacing with 8051 microcontroller pdf
relay interfacing with avr microcontroller
interfacing relay with microprocessor
relay interfacing with dc motor
interfacing relay with msp430
interfacing relay to microcontroller 8051 tutorial
interfacing of relay with 8051
interfacing of relay with microcontroller
interfacing of relay with pic microcontroller
interfacing of relay and dc motor
interfacing of relay with 8051 microcontroller pdf
interfacing of relay with lpc2148
interfacing of relay with 8051 pdf
interfacing of relay with atmega16
interfacing of relay with 8085 microprocessor
relay interfacing pdf
interfacing relay pic microcontroller
relay interfacing with pic16f877a
relay interfacing with pic
relay interfacing in proteus
relay interfacing with 8051 pdf
relay interfacing with 8051 ppt
interfacing relay with parallel port
interfacing relay with parallel port uln2803
relay interfacing with 8051 microcontroller pdf
relay interfacing to 8051
relay interfacing to microcontroller
interfacing relay to pic
interfacing relay to pic microcontroller
interfacing relay to microcontroller 8051 tutorial
relay interfacing with transistor
interfacing relay modules to arduino
relay interfacing with uln2003
relay interfacing with uln2803
relay interfacing with 8051 using uln2003
relay interfacing with 8051
relay interfacing with arduino
relay interfacing with 8051 pdf
relay interfacing with microcontroller
relay interfacing with lpc2148
relay interfacing with 8051 microcontroller
relay interfacing with 8051 microcontroller pdf
relay interfacing with atmega16
relay interfacing with pic16f877a
relay interfacing with pic microcontroller
interfacing 12v relay with 8051
relay interfacing with pic16f877a
interfacing 5v relay with 8051
relay interfacing 8051 circuit
relay interfacing 8051
relay interfacing with 8051 pdf
relay interfacing with 8051 ppt
relay interfacing with 89c51
relay interfacing with 8051 microcontroller pdf
relay interfacing with 8085
relay interfacing with 89c51 microcontroller
relay interfacing with 89c52
interfacing relay to microcontroller 8051 tutorial