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Relay 5V

In this article we will talk about relays.
The relay is a device that permits with a small voltage to pilot a reed switch.
How this device should be applied on the circuit ?
How can we place it on an arduino ?
All these answers will be cleared in a while.
Let's start with some theory to see what happens in detail.
At the top of the relay we can see the 5V as input pilot voltage.
And we can see the 10A limitation at the 250VAC of the reed switch.
So with a 5 Voltage we can "switch" a 250VAC device that can consume up to 10A (P=V*I=2,5KW).
If you need to pilot a device that consumes more you should use a "bigger" relay that fit at your needs.

...continue reading "Relay and arduino"

Common Emitter is an expression to indicate exactly an electrical configuration where a part on three of BJT transitor (and only that kind of transistors) is used as reference for the other two.
So keep in mind it's impossible to make confusion with other contexts.

But... what's an emitter, or a transistor? why bjt? I'm instead confused!
And you're right if never seen one of them, neither in theory exposition.

Generally a transistor is a semiconductor device which you can regulate voltage and/or current in output with; maybe its name's explanation could give a bit of information more: transistor is the contraction of "transfer resistor".
According to their inventors it's been so called "because it's a resistor or semiconductor device that can amplify electrical signals as they are transferred through it from input to output terminals". ...continue reading "Common Emitter. Why and how to"

In this lesson we will see what are the main characteristics of an Operational Amplifier.

We will try to understand what are the values that should characterize the ideal case.

And, finally, we will see how much the real case is close to the ideal case.

An ideal operational amplifier should have the following four characteristics:

  1. ...continue reading "4 – Op Amp: Ideal and real characteristics"