00:02In this video, we will talk about the power semiconductor device; we have the
00:08Power diodes are characterized by the fact that, in the conducting state, they must be able to
00:12to withstand high intensity with a small voltage drop.
00:16Here we have a semiconductor in its structure and power.
00:21The Thyristor or SCR, this is mainly used in high power control devices
00:27and converts high alternating currents into direct currents.
00:31Like a normal PN junction diode, the SCR is a current control device
00:37unidirectional, it allows the passage of electric current in only one direction and blocks
00:41the passage of electric current in another direction.
00:45A typical P-type and N-type diode is made of two layers of P-type semiconductor material.
00:50and type
00:51N.
00:52However, an SCR diode is made of four semiconductor layers of alternating materials
00:58type P and type N.
01:00The anode is a positively charged electrode through which the current enters, the
01:04The cathode is a negatively charged electrode from which the current flows; the gate controls
01:09the flow of current between the anode and the cathode.
01:13Here we have the different types of curves: anode, cathode, input voltage, and
01:19the gate, with a firing angle.
01:25Now, to simulate the firing angle and operation of an SCR, we will do the following:
01:30In Multisim, we input the elements to be simulated, an alternating current source,
01:40a single-phase transformer, a thyristor or SCR, a pulse voltage signal, or a generator
01:55of signal, a load or resistance in this case a 12-volt lamp and of power
02:0125 watts, with a resistance of 5.76 ohms.
02:29And we made the connections.
02:592.76 ohms.
03:01To measure the input and output voltage of the transformer.
03:062.76 ohms.
03:23We changed the configurations of each element; for the AC power source, it will be
03:28220 volts, and 60 hertz.
03:36The transformer will be the configuration used in a video seen previously, here in the
03:41The primary winding will have 1000 turns for a voltage of 220 volts, and the winding
03:46The secondary winding will have 55 turns in order to perform the simulation.
03:55Initially the pulse voltage is 1 volt.
04:02The signal or pulse generator, the pulse will be 0.5 milliseconds.
04:10The period will be 16.6667.
04:15We're looking for the frequency period; we have 60 hertz, so we do 1 divided by 60 hertz.
04:21This gives us 0.016666 seconds; to convert it to milliseconds, we transform and divide.
04:271000, we get 16.6667 milliseconds, we replace, in the window in period, we also have,
04:34In the 90-degree phase analysis, we first made the oscilloscope connections
04:43The probe will be connected to the load, the resistor, and channel 1 will be connected to the power source.
04:53AC, channel 2 will be connected to the AC power source, channel 2 will be connected
05:04To the gate of the SCR, channel 4 will be connected to the load, in this case the 12V lamp
05:15volts.
05:18Before simulating phase analysis, the operating angle is 90 degrees.
05:23of the SCR.
05:31We proceeded to measure the time the SCR is active from the moment it receives the pulse.
05:36Observe in the image how the SCR begins to conduct when it receives the pulse and then shuts down.
05:40of the 4 milliseconds, this is when the input signal reaches 0 and begins its cycle
05:45negative, causing the SCR not to conduct until the input wave reaches it again
05:50higher, which is where the shot is located.
06:01The yellow power waveform is at its highest point during the firing signal.
06:07The blue part is located in the same place and that's where the thyristor starts conducting.
06:24That's all. If you found the video helpful, don't forget to subscribe.
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