Basic components

This week i can't say that i have much to report on as I have been absent from two of my four lessons in the past week as of the business with my mom travelling out of the country and the loss of my uncle. From what I did pick up last week is that we learnt about diodes and relays.

    A diode, to my general understanding, is a component that allows current flow in one direction but not in the other e.g. allows current flow from the positive to negative terminals, but not from negative to positive. A diode can be either a consumer (e.g. a LED) or not. Its purpose is to ensure current flows in a desired direction within a circuit. Ofcourse there are many types of diodes but due to my inability to wake up in time to wake up early enough to attend the lecture i am not able to report on the design and functionality of the other types of diodes.

   A relay is a tad more complex than the diode and I warn any that may read this that my the following shouldn't be anything to go by. My general understanding of a relay is that it is a switch that consists of a electromagnet and several contact points as shown in the picture to the left. In the picture it shows an open switch (which is in parallel) which means that the no components in the circuit will be powered. If one were to flip the switch, then the electrons would the flow to the control coil which would produce an electromagnetic field within the iron core, which would in turn pull the the two contact points together and let electron flow to the load (component) at the other end of the circuit. When the switch is flipped again the electromagnetic field collapses and the connection between the contacts is broken, cutting of the flow through that circuit. More often than not there is a spring that would return the contacts back into their original position.

A Transistor is basically a rapid switching relay.






 "The essential usefulness of a transistor comes from its ability to use a small signal applied between one pair of its terminals to control a much larger signal at another pair of terminals" as shown the diagram below. This transistor is positively connected, meaning that the transistor is controlling the positive side of the circuit. The base is the wire which connects and disconnects the current flow between the emitter and the collector. 

A transistor may be used instead of a relay because:

No moving parts
Requires no maintenance
Switching is silent & instantaneous
Not affected by vibration