Why buffer is used between micro controller and relays?
Buffers usually provide protection to the microprocessor from what is called, `back EMF`(also called spiking) in layman's terms, or the energy created in the coil as the control voltage is released. Also, since most micro's have limited output current capabilities, the buffer could serve as a relay driver, providing the power necessary to energise the relay.
Hope this helps,
Cubby is right, mostly the maximum current that a micro controller can source or sink is 25ma, where as most of the relays require 50ma-200ma so a buffer is required to provide the necessary current to activate the relay coil, moreover a back emf is generated when the relay is turned OFF which can damage the controller so buffer also protects the controller from this back EMF......check this link to know more about interfacing relay to a micro controller
How do you drive a motor requiring 2.6 ampere current using a micro controller whose output is 5 V and current in milliamperes?
Registers are a special type of memory that are dedicated to micro-controllers (or CPUs). Controllers have register-memory for speed. The slowest part of any computer is the bus. The bus is the wiring that connects different components. In this case the micro-controller and main memory. While main memory and the micro-controller are both very fast, the wiring between them is slow. Should the micro-controller have to be slow to compensate for the slow wiring? The…
1) Define the functions the product will perform. 2) Design the hardware that will allow the functions to be implemented. 3) Design the logic that will allow the functions to be controlled (controller). 4) Design the interface between the micro-processor and the controller. 5) Code the function performance into the micro-processor. 6) Market it.