First day of Electrical and Electronics. We study ohms law with 3 formulas :
1.Voltage(V)= Current(I) x Resistance(R),
2. Current(I) = Voltage(V) / Resistance(R),
3. Resistance(R)= Voltage(V) / Current(I).
at the bigginning of the class.
And later on, we start working on a series circuit.
To build a series circuit, we connected the board to a power source,
put a positive wire to the fuse and a wire from the fuse to the switch,
a wire from the switch to a light bulb and wire back to the negative of the battery.
This was our first circuit we built.
We then built up a circuit consisting of the exact same components with 3 big light bulbs connected in series
To caluate the current through the series circuit, we break the circuit at different point so that the multimeter
becomes part of the circuit. what we have learnt from the series circuit is that Current remains same
all the way through.
Wednesday 06/04
After working on the series circuit, we move on to the parallel circuit today.
To build up a parallel circuit we set the board up from the power source. From the positive to the fuse and from the fuse to the switch. From the switch we had 2 wires running to 1 light bulb each, and from both light bulbs a wire was connected back to negative of the battery. We measured the available voltage and voltage drop at different points.
To measure voltage anywhere in a circuit, it must be connected in parallel. When you measure the voltage drop in a particular part of a circuit, the multimeter must be connected to the input and the output of the component you want to measure. Whereas when you measure the available voltage, the black probe of the multimeter is connected to the negative of the battery and the red probe is connected to the component you want to measure. Otherwise the fuse will be destroyed....
Thursday 07/04
we build up a circuit with both series and parallel in one circuit.
This circuit consisted of 2 big bulbs in parallel and one bulb in series,
with a fuse, switch and power supply. From the positive battery,
a wire was connected to the fuse and from the fuse to the switch.
From the switch, we need to make a junction because it is a special circuit.
One of the parallel bulbs negative was connected to the positive of the bulb in series.
The negative from one of the parallel bulb and the negative of the series
was connected to an another junction which was then connected back to
the negative battery to create the circuit.
We measured the voltage, current and calculated the resistance of each bulbs
in the circuit using the formula: R(Resistance)= Voltage(V) / Current (I).
We then calculated the Watts of each bulb using the formula W(Watts) = V(Voltage) x I(Current). We noticed that the two bulbs in parallel are much dimmer than the one bulb in series.
This is because the bulb in series is consuming most of the voltage of the power supply and in parallel circuit, the current is devided equally through the bulbs.
The available voltage at the two parallel bulbs were 8Volts and at the bulb in series
the voltage available was 0V.
Friday 08/04
Today we make the LED tester.
This was basically a tester to check for power in a power source like a car battery.
To make this, we use A brass rod as the conductor 1 red LED and 1 green LED, a black wire 2 meters long, 1 black alligator clip, 1 red alligator clip, plastic tubing and some shrinking tubes.
today work was bit harder than last 3 days. The reason why is that when we worked on the circuit,
we worked together as a team which means in order to build up the circuit, we discuss how to connect
the wire and where to connect the wire. This however, we have to do by ourselves. On the other hand,
it is also funny to make LED tester.
Over all, everything we did this week was fresh shock to me. Because i haven't study this kind of
subject before and didn't know how to explain and how to write. By learning this, i'm getting more
information on electronic thing.
