# Simulate, Analyze, Measure Electronics (SAME)

In Electronics, there are 3 perspectives of a circuit

1. Simulation - simulate to observe what the real world results should be like
2. Analysis - using mathematical models to analyze and predict the results
3. Measurement - prototype the circuit and measure
If the results from the 3 perspectives are the SAME, one can independently conclude that the result is correct. This is a good way to learn electronics and indispensable when one needs to modify an existing circuit or design a new circuit.

## We like short equations

An equation with more than 2 fingers width on each side of the equation is not very useful in design

The voltage gain of a common emitter amplifer can be written as

or this shorter version

$$A_V = -{R_C \over r_e} = -{{R_C I_E} \over 26mV }$$

On this site, we prefer the shorter one - because it enables the reader to see quickly that the main determinants of the voltage gain are the parameters RC and IE. This is the first order effect. The long equation is more useful for higher order analysis.

## The odds are against you in the lab

The odds are overwhelmingly against the learner to get a new circuit working right the first time
Dr GH Tan

The circuit shown is a simple LED circuit. The circled parts of the circuits are the places where the learner has to wire or orientate the part correctly. Lets say that there is a 1/2 chance of getting each action done right. The circuit works if and only if all the actions are done correctly and the probability of that happening is

$$P = {1 \over 2} \times {1 \over 2} \times {1 \over 2} \times{1 \over 2} = {1 \over 16}$$

So you have actually better odds guessing the outcome of a coin toss then getting this 'simple' circuit wired up correctly the first time you attempt it.

We improve the odds by

• using a breadboard simulator to check the wiring.
• using online simulation to show the user the outcome of a correct circuit operation.