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Electrician Tools


With the multimeter it is possible to carry out measurements of the electrical quantities

mentioned above and in some multimeters there are also functions such as: temperature in Celsius and Fahrenheit, semiconductor (diode) test, conductor continuity

test and Duthy Cicle signal percentage. Now let's see how to use it on several occasions.

Using the Multimeter

To measure direct current voltage we must:

Place the multimeter on the Continuous Voltage scale.

Place the probes correctly in the source that we want to measure the Voltage, positive side red tip, negative side black tip.


To measure Diode and Continuity of a conductor we must:

To Measure Electric Current we must:

Open a consumer's electrical circuit

Place the red tip at the end of the circuit

that is open and the black tip at the other end as shown in the figure.

Note: Current Test must be done for a maximum of ten seconds if for a maximum

current of ten amps.

HOW USING multimeter


Using the Oscilloscope

The oscilloscope is an essential piece of equipment in the repair of electronic centrals, as with it it is possible to diagnose the traffic of electrical signals in the electrical circuit. For example; with it we can identify if the processor is sending a coil's firing pulse, if this pulse is leaving the responsible component  and if it is reaching the switch's nozzle connector.

Now let's see how we can use the oscilloscope and what are its most important settings. With this understanding it will be possible to interpret any signal on any oscilloscope.


Interpreting the Oscilloscope

Before reading the measured waveform parameters, we have to check what the value of the time base adjustment and the voltage scale are configured. In the example below we have:

Time base: equals 10 ms per division. It means that the horizontal scan takes 10 ms to scan the space of a horizontal division of the screen.

Voltage range: 5V per division. It means that a variation of 5V in the input signal corresponds to a vertical division of the screen.

Interpreting the Oscilloscope

So, we can conclude that:

The signal amplitude is (2 divisions) x (5V per division) = 10V.

The negative pulse width is (1 division) x (10 ms per division) = 10 ms.

The positive pulse width is (2 divisions) x (10 ms per division) = 20 ms.

The period is (3 divisions) x (10 ms per division) = 30 ms.

Interpreting the Oscilloscope

Adjusting the Oscilloscope

Oscilloscopes basically have 4 main settings:


Time base.

Voltage scale.

Trigger Offset.

We can make the X axis of the drawn waveform be in the center of the screen or in

another position as per our convenience.

time base

With this setting we can choose the speed of the screen's horizontal sweep. Note that in both measurements the period of the waveform is 30 ms.

voltage scale

With this setting we can choose which input signal voltage value will be represented by each vertical division of the screen. Note that in both measurements the voltage amplitude value is 10 V.


The trigger (Trigger) is a feature that synchronizes the oscilloscope's time base with the measured signal, preventing the trace from sliding horizontally. This makes the trace drawing of the measured waveform stable on the screen. The figure below illustrates a measurement with the trigger misconfigured and, on the right, the same measurement with the trigger correctly configured. With the trigger active, the oscilloscope stops drawing the waveform every time the sweep reaches the far right of the screen and only starts drawing the new trace if the trigger event occurs. This causes the waveform to always be drawn from the same point. The trigger event occurs when the measured waveform reaches the value and direction (ascending or descending) determined by the user.


Common Wave Types

Common Wave Types

With the Oscilloscope we can observe the electrical signal in its minimum and maximum amplitude, observe the cycles and frequency with which the signal occurs, in addition to analyzing the integrity of this signal (if there are no interruptions).


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