Monday, February 8, 2016

Revision of Circuits and Electronics Part 1 - The Digital Abstraction (lecture 4)

Node method can be used in all cases.

Analog systems lack noise immunity.

So values need to be discretized - high and low ( 1 and 0)

If we take 2.5V to be the midpoint for 0 and 1 and if the voltage sent  is 2.5V , it won't work so a forbidden region is needed.

If we set a forbidden region between 2V and 3V, there will still be problems because of a lack of noise margin. So the solution is to set tougher standards for the sender. For example, between 4V and 5V for a 1  (V_oh)  and between 0V and 1V for a 0 (V_ol).

The rest of the lecture is on digital circuits which I am not going to cover much about as I am quite familiar enough about that topic.


Lecture notes : - 

Monday, February 1, 2016

Other Side of the Screen Cover by me

Yep, I actually sang a song and it's in Youtube!

Thank you for the song -
Download/Buy Emily's song -

Watch Emily's official artist video!  -

Support mSb!  -

Wednesday, January 27, 2016

Revision of Circuits and Electronics Part 1 - Superposition, Thévenin and Norton (lecture 3)

What are the properties of  a linear circuit? It has homogeneity and superposition properties.

Homogeneity means a proportional input and output.

Superposition involves -

(1) Finding responses of the circuit to each source acting alone.

(2) Summing the individual responses.

This applies to independent sources.

Thevenin's Theorem -

VTH  -  Open circuit voltage seen at the terminal
RTH -     Resistance of network seen from the port.

Norton's theorem  -
 IN  -  -Short circuit current seen at the port
RN -     same as Thevenin's resistance

Video: -

Lecture notes : -

Tuesday, January 26, 2016

Revision of Circuits and Electronics Part 1 - Circuit Analysis Toolchest (lecture 2)

KCL and KVL are basic methods but nodal analysis is now quite popular. The steps are:-

(1) Select reference node (ground) from which voltages are measured

(2) Label voltages of nodes w.r.t. geound

(3) Write KCL for the nodes

(4) Find required voltages and nodes.

Video: -

Lecture notes : -

What's Buzzing?

I was doing all the things that an independent artiste should do - registering for Soundexchange and trying to get my music on radio. The process takes time as Soundexchange may take up to 30 days to reply.

I am glad I am back to doing some electronics again. It's a tough subject so I  am going slow with it. 

Monday, January 25, 2016

Revision of Circuits and Electronics Part 1 - Lumped Circuit Abstraction (lecture 1)

Suppose we wish to answer a question like-
What is the current through a bulb?

 We could do it the hard way  with Maxwell's equations or the easy  way where certain conditions are ignored. So to do it the easy way, replace the bulb with a discrete resistor and use Ohm's law to find the current. The discrete resistor becomes the lumped element abstraction of the bulb.

From Maxwell's equations, a problem arises where  the rate of change of charge w.r.t. time may not be equal to zero when finding the current.

(1) To be unstuck from this problem, we have to make it equal to zero!

(2) The voltage also needs to be defined and for this, rate of change of flux  w.r.t. time outside the element is equal to zero.

(3)Signal speeds should be less than the speed of light.

The above is not really true in general but  is the playground for EECS.

KVL- sum of voltages in loop is zero
KCL- sum of currents in node is zero


Lecture notes:-