Circuits of test of components
It is to emphasize that all these circuits will not serve to determine us the degree of good operation of the components but they will only indicate if the same serves or not, that is to say that they will reveal to us if the circuit under test is in short circuit or open circuit.
If we wished to obtain the beta of a transistor PNP or NPN we will have to use the circuit that is in Test of ganacia for transistors
Also it is possible to obtain the polarity of a tension with the indicating circuit of polarity, and to prove the continuity of a circuit or component with the probador circuit of continuity.
In order to prove the SCR´s we will be able to use the following probador of SCR´s.
Circuit for test of rectifying silicon diodes:
By means of this circuit we will be able to see if a rectifying silicon diode apt for 220 V rectifies or no. If the diode that we are trying finds in good conditions, under the conditions indicated in figure 1, the lamp will encederá to means brightness and when closing itself the key, the lamp will increase its intensity of brightness.
Figure 1
If a change of luminosity does not take place it means that the diode is in short circuit, that is to say that the 220 at any moment lamp received V. However, if the lamp did not ignite with the open key and it did if it when this was closed, this indicates to us that the diode is an open circuit.
Circuit for test of rectifying diodes of silicon of low tension:
Also with this circuit we will be able to see if the diode rectifies or no. the diodes are excepted 1N34A, 1N270 and 1N914, for which the circuit is the one of figure 3.
When a diode is connected as it indicates figure 2, connecting the source of tension with the indicated polarity, the foquito will have to ignite; when the polarity of the battery is invested, the center no longer will ignite, this way it will be indicating to us that the diode rectifies.
Figure 2
Like in the previous case, if the foquito ignites, independent of the polarity of the battery, the diode will be in short circuit. However, if the lamp does not ignite with any polarity, the diode is working like an open circuit.
When it is wanted to prove a diode type 1N34A, 1N270 or 1N914, as we have mentioned or it, the circuit of figure 3 will be used, when it is connected to the diode between terminals 1 and 3 with the anode to terminal 1, the lamp will ignite when the diode is in good conditions, investing to the diode, the foquito must go out, if this one remains ignition in both connections, means that the diode is in short circuit, if, on the contrary, it does not ignite in any of the two connections, this one this in open circuit.
Figure 3
Probador of bipolar transistors:
In figure 4 we appreciated a probador for bipolar transistors, the connections are you throw for a transistor n-p-n. When connecting the resistance to the positive terminal of the battery, the center must ignite when the transistor works correctly, but we changed the position of the resistance to the negative terminal of the source, the center must go out. If they are desired to prove transistors type p-n-p it will be necessary to invest the polarity of the battery to obtain the same results.
Figure 4
In case of not counting on these circuits, or to want to realize a verification rápìda before connecting them in a circuit the resistance between the electrodes can be measured. The typical values between two electrodes any are very high (more than 10 Kohms) in a direction, and much smaller in the other (100 ohms or less between emitter and bases or collector and bases and approximately 1000 ohms between emitter and collector).
Probador of controlled silicon rectifiers:
The assembly of figure 5 is apt for rectifiers able to only support 220 inverse tensions of V. When the key is closed approximately circulates a current of 40 mA around the lamp, the resistor and the key, which is insufficient to ignite the lamp. When abrir the key the lamp will ignite to means brightness. If the lamp ignites to total brightness it means that the rectifier is in short circuit, and on the contrary, if the lamp does not ignite when operating the key the rectifier is in open circuit.
Figure 5
For transistors of type MOS there are no circuits of test of the type BUT, the good operation of the same will be only known observing its behavior in a certain circuit.
For the integrated circuits either it is not counted on this type of circuits of test, a good form to verify the good operation of the same is by means of the data sheet of the same, from where we will be able satisfactorily to obtain data about the tensions in the legs of the integrated circuits once installed in the circuit and working the same.
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