• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Facts for beginners using A Arduino

be80be

Well-Known Member
Thread starter #1
There a lot of people would have you to think that the ATmega328P can source and sink 40mA. a pin

First off it's Absolute Maximum Rating is 40mA but this is basically a one pin per port, Not all 23 I/O

And the chip can only sink or source 200mA from gnd and VCC

A port can only sink or source 100mA

What this means is don't use more then a port can output when figuring you hardware

Like if you need to drive a relay use a 2n3904 or a 2n7000 with base or gate resistors and a kickback diode

Light a led use a resistor need more power use a driver 2n3904 or a 2n7000 for small loads up to 200mA and look up better options for bigger loads.
 
#2
There a lot of people would have you to think that the ATmega328P can source and sink 40mA. a pin

First off it's Absolute Maximum Rating is 40mA but this is basically a one pin per port, Not all 23 I/O

And the chip can only sink or source 200mA from gnd and VCC

A port can only sink or source 100mA

What this means is don't use more then a port can output when figuring you hardware

Like if you need to drive a relay use a 2n3904 or a 2n7000 with base or gate resistors and a kickback diode

Light a led use a resistor need more power use a driver 2n3904 or a 2n7000 for small loads up to 200mA and look up better options for bigger loads.
It's all ports, the sum of the current cannot exceed 150mA, not 100mA per port.
A PN2222 or 2N2222 is also a good transistor to use as a driver, or ULN2803 8 channel drivers (built in resistors for 5V operation).

2N7000s are FETs, finicky, and blow up very easy, not recommended by me.
 

Latest threads

EE World Online Articles

Loading

 
Top