The simplest case occurs if the body diode has the symbol. It consists of an equilateral triangle and cut a straight line, in which the triangle rests on one of its corners. On diode's, marked by a new standard, this designation would further like crossed - the essence remains the same. Let's see how precisely focused the designation on the findings of the diode: the one that is closest to the triangle, corresponds to the anode, and the one that is closest to a line segment - the cathode.
If you know exactly what type of diodeand there is a guide or Datasheet to determine the polarity. View, about which conclusions should be the point (or several points) or a circle. Sometimes by number or color dots, you can optionally specify the prefix of the diode within a series, and it in turn is the maximum reverse voltage.
If the diode has no signs and all you know about him is the forward current and reverse voltage, determine the polarity in the following way. Take an ohmmeter (or multi-function apparatus, which has such a function). Determine the polarity of the voltage on its probes in the measurement mode of resistance, using as a model the other diode, the Pinout is known. Then, connecting the test probes to the diode of the subject in different ways, determine the location of its electrodes at the analogy.
Very useful for determining the Pinout of the diodes use a special probe. Take two penlight batteries, a led, a resistor of 1 kilo Ohm and two testers. All the parts connect in series, and the polarity of the inclusion of the diode determine experimentally that with the closure of the probes it was glowing. The test diode, connect the probes, first in one polarity, then in another. When the led glows, the output of the diode isfacing the negative pole of the power source is the cathodemodulation.
Do not connect measuring instruments to the circuits under voltage.
Advice 2: How to determine the polarity of the diode
Any diode changes its conductivity depending on the polarity of the applied voltage. The location of the electrodes on his body indicated not always. If labelling is missing, to determine which electrode is connected to what pin, you can own.
First, determine the polarity of the voltage on the probes that the measuring device you use. If he is rich, put it in the mode of the ohmmeter. Take any diode on the body which indicated the location of the electrodes. This designation of "triangle" corresponds to the anode, and "strip" the cathode. Try to connect the probes to the diode in different polarities. If it conducts current, then the probe to the positive potential connected to the anode and negative to cathode. Remember that the polarity in the mode of measurement of resistance to pointer instruments may differ from that which is provided for measuring voltage and current. But on the digital devices it is usually the same in all modes, but to check still won't hurt.
If checked the vacuum diode with direct heat, first locate it a combination of pins, between which the current flows regardless of the polarity of connection of the measuring device. This - the filament is the cathode. Through the directory, find the rated filament voltage of the diode. Served on the filament DC voltage corresponding value. The probe of the device, which is a negative potential, connect to one of the pins of the filament, and the positive probe touching turns to the rest of the insights of the lamp. Upon discovering the pin, when you touch the probe to which displayed resistance, lesser infinity, conclude that it is the anode. Powerful vacuum diodes with direct heat (rectifier tubes) can have two anode.
Vacuum diode with indirect heat heater insulated from the cathode. Finding him, sue him alternating voltage, the effective value of which is equal to the specified reference. Then among the other insights find the two between which at a certain polarity passes current. The one that is connected to the test lead with the positive potential, the anode is opposite the cathode. Remember that a vacuum diode with indirect heat have two of the anode, and some two cathodes.
A semiconductor diode has only two pins. Accordingly, the device to be connected to only one of two ways. Find a element position at which the current is passed through it. Test lead with the positive potential will be connected to the anode and negative to cathode.
Advice 3: How to identify the anode of the diode
A diode has two electrodes, called anode and cathode. It is capable of conducting current from the anode to the cathode, but not Vice versa. The marking that explains the purpose of the findings is not available on all diodes.
If marking is available, note its appearance and location. It looks like the arrow rests on the plate. The direction of the arrow coincides with the forward direction of the current flowing through the diode. In other words, the arrow corresponds to the anode terminal, a plate - cathode.
Analog multi-function measuring devices have different polarity of the voltage applied to the probes of the ohmmeter. Some of them she's just like using a voltmeter or ammeter, others - the opposite. If it is unknown to you, take a diode, marked, switch off the device to the ohmmeter, then connect to the diode first in one and then in the other polarity. In an embodiment in which the needle, remember which electrode of diode were connected to which of the probes. Now, connecting the probes at different polarity to other diodes, you will be able to determine the location of their electrodes.
Digital devices in most cases, the polarity of the probe in all modes is the same. Switch the multimeter mode of the diode is next to the switch there is a designation of that part. The red test lead corresponds to the anode, black - cathode. Correct polarity will show the forward voltage drop across the diode in the wrong is indicated by the same infinity.
If the measuring device is not, take the battery from the motherboard, a led and a resistor to one kilo Ohm. Connect them in series by connecting the diode in such a polarity to the led light. Now include the gap of this circuit check the diode, experimentally picking up a polarity to the led lit up again. The output of the diode facing the positive battery anode.
If you review the impact that the diode is permanently open or permanently closed, and the polarity does not depend on anything, then it is faulty. Replace it, after making sure that his failure is not due to a malfunction of other parts. In this case, first replace them.
All perepiski do with the equipment de-energized and discharged capacitors. Diode check vipanna.
Advice 4: How to determine the directional angle
Directional angle – geodetic title direction angle of the orientation lines on the map relative to the geographic or magnetic Meridian. The angle is determined directly on the map or a magnetic azimuth.
You will need
- - map of the area;
- - pencil and ruler;
- - protractor, artillery round or chordophones;
- - the compass or the compass.
There are several ways to determine the azimuth angle: the map or aerial view with a protractor, hormogonia or artillery round, and on a magnetic azimuth using a device with a magnetic arrow.
To determine the directional angle using the protractor, find the map the initial point and the object on the ground (landmark), mark them. Using pencil and ruler draw a line. The length of the line should exceed the radius of the protractor, starting from a point of intersection with the vertical line of the graticule.
Place the protractor on the map so that the "zero" on the protractor coincides with the vertical line and the centre – point of intersection of the lines. Count directional angle according to the scale of the protractor on the line drawn between objects. Measurement of an artillery round similar to the use of the protractor. The center of the circle coincides with the origin, and zero mark – with the North direction of the vertical grid lines, or with straight, parallel to it.
For measurements using hormogonia draw a line between the original point and the reference point is not less than 15 cm From the point of intersection of this line with the vertical through circulatorios make notches on the lines forming the acute angle. To do this, swipe the arc of a circle with a radius of 10 divisions of the instrument. Then put a compass with two needles at the marked points, thus making the solution of the compasses equal to the chord length (distance between points).
Holding both the needle of a compass is on a horizontal line, lead it to the left needle at the leftmost vertical scale of hormogonia. Continue until, until the right needle is not matched with the line of intersection, horizontal or inclined. Remove the dimension.
To determine the azimuth angle using a magnetic bearing use the compass or other device with a magnetic arrow, for example, the compass. In order to use this method, it is necessary to know the correction direction. This is the amount of deviation of the magnetic Meridian (magnetic needle) that point from the vertical line of the graticule. The amendment direction is usually indicated on the map in a frame.
Determine a magnetic azimuth, measured clockwise from the North direction of the magnetic Meridian (direction of the magnetic needle of the device) to the designated direction. Directional angle find by the formula:α = β + (±dα), where β is the magnetic azimuth, dα – the correction direction.