DAY 2

Today was a busy day.

We got 3 handouts.

1. Using the multimeter

2. Introduction to using breadboard

3. Schematics, Ohm's Law and Potentiometers

Using the Multmeter:

Primarily we did mini exercises on continuity measurements, resistance measurements, and voltage measurements. On the continuity test, we used the ohm or resistance measurement of the multimeter. We used the circuit board we mad and check for breaks in the circuit. Since continuity in the circuit is non-directional, we can probe the board in any directions. We tuned the meter to a short-circuit beeper and so if there is continuity, it would beep. Resistor above a 100 ohm did not beep. Large capacitor beeps, small do not. OL also shows that the circuit is not connected.

Voltage Testing:

We learned of the science of AC/DC source. Alternating Current versus Direct

Current. I used the 5V power supply/transformer from yesterday as the main power source; the transformer steps down the 120V AC down to a 5V DC. To check voltages, we switch the mulitmeter's mode to DC Voltage. Using the probe, we test across 9V and 1.5V D batteries. Voltage is testable only when the circuit is powered on. In case of odd readings, use a "reference voltage" at hand to check if the meter working properly. Since voltage is directional, you can get positive or negative reading; regardless, always have the black probe on reference or ground. Lastly, we tested the wall wart. On a unregulated wall wart, the voltage measured is AT LEAST what's printed on the case. We used a 13.3 V unregulated rated at 12V which measure the voltage to be 11.1V with a 470 ohm resistor. However, a SWITCH MODE adaptor is lighter and smaller and are regulated. The one I made from yesterday was rated at 5.1 V and the meter reading was at 5.11V, incredibly accurate.

We also tested the wall output using the voltage meter. We measured it at 121.8V. In addition, we tested 5 resistor and learn to read the color of the resistors for it's value in resistance. A good mnemonic rhyme is Bad Beer Rots Our Young Gut But Vodka Goes Well, 0123456789, respectively. Lastly, we worked with a potentiometer and light sensor. The potentiometer acts like a logarithmic variable resistor and the light sensor increases in resistance with less lumens and decrease in resistances in more lumens.

Resistor Reading: