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How can the cathode end of a zener diode be determinded using an ohmmeter?
Wiki User
∙ 12y ago
Hard to do. If your Ohmmeter battery is just 1-1/2 volts, then you simply put the test leads on the diode one way, then the other way. The way that show a meter reading will have the black lead on the 'cathode', if you assume, as most do, that electrons are issued from the " - " or 'minus' side of the battery.
BUT . . . if your Ohmmeter voltage is above the zener's trigger voltage, then you will get a reading both ways.
Wiki User
∙ 12y ago
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How could unmarked diodes have its cathode leads identified using an ohmmeter?
Assuming the red lead of the ohmmeter is more positive than the black lead, then checking the impedance of the diode with the ohmmeter, in both directions, will identify the cathode as the black lead when the measured impedance is low. This, however, will only work if the voltage developed by the ohmmeter is greater than the forward bias voltage of the diode, typically 0.7 volts.
How can the terminals of the diode be identified using the ohmmeter?
More commonly, the RED probe is on the banded (cathode) end of a diode, when the meter reads. You can also use a high ohms range (try around 200K) with a digital ohmmeter, not all have a specific "diode" setting. So test the meter first with a known marked diode, one that has a band on 1 end. You should get a reading with the probes around 1 way, and not the other. The probe on the banded end when the meter reads is the negative lead. Usually, that's the red one. So testing future diodes, if the meter reads, the red is the cathode of the diode. The polarity of the voltage appearing between the probes of digital and most analogue meters is opposite. The red lead of a digital meter is positive on the ohms ranges, while on most analogue meters the red lead is negative on the ohms ranges.
How can you reduce back current while using relay?
You put a diode in parallel with the coil. The cathode end of the diode connects to the plus side of the coil and the anode connects to the negative side. The cathode is usually marked with a line at one end of the component.
How do you find the AC input and anode rathode of a brige diode using VOM?
A: On a bridge rectifier there are two diode connected in series and in series with the load they only conduct once per cycle positive then the other two take over for the negative cycle . At the load positive the diodes will be two cathode tied together at the negative side there is two diode where the anode are tied together. either cathode anode tied together that is the ac. You cannot use an ohmmeter to check for faults this way since the load and the transformer resistance are in the way. Must remove the bridge to check it.
Can you use transistor as diode?
its the simplest thing to do. There are three legs in a transistor, one each of collector, base and emitter. So if you need to use it as a diode, just connect either collector-base or emitter-base. Say, if you use an NPN transistor, then the base region will be the anode of diode and emitter or collector will be the cathode of the diode.
What is the main rule to be followed when using an ohmmeter?
The main rule to be followed when using an ohmmeter is to have the circuit under test de energized from the power source.
Should the ohmmeter be connected to the circuit while the power is being applied or only when the circuit is turned off?
Turn off the supply before using the ohmmeter,it will damaged your ohmmeter when supply is present.
How the resistance is measure?
Using an ohmmeter, Wheatstone bridge, etc.
How would you determine if the diode were good or defective?
Firstly, to be absolutely certain, one leg of the diode should be unsoldered and lifted from the Printed Circuit Board (PCB). There are many considerations here:- The Power must be disconnected from the device, you will need a suitably sized soldering iron, you will need a solder sucker or wick and solder to reinstall. Some previous soldering experience would also be valuable. Secondly, you will need a Digital Multimeter (DMM) with a diode test function. Assuming the above, identify the Anode and the Cathode of the diode as follows: The Cathode is generally marked with a painted or etched band or stripe. Using the DMM, switched to the Diode Symbol, red lead plugged into the + terminal, black lead plugged into the - terminal, put the red lead on the Anode and the black lead on the Cathode of the diode. A good silicon diode should indicate between 0.6 & 0.7V on the display of the DMM. Reverse the lead connections at the diode and the display should read "OL", which means the maximum reverse voltage is applied and no current flows. An indication of 0V in one or both directions or OL in both directions means a faulty diode.
What precuation must be taken when using an ohmmeter?
Be certain the circuit is de-energized and discharged before connecting an ohmmeter.Do not apply power to a circuit while measuring resistance.When you are finished using an ohmmeter, switch it to the OFF position if one is provided and remove the leads from the meter.Always adjust the ohmmeter for 0 (or ∞ in shunt ohmmeter) after you change ranges before making the resistance measurement.
What does the silver band on a car electrical diode mean?
The silver band shows which end is the negative (Cathode) end. If you are using it as a blocking diode, the other end (+ve Anode) should be connected to the +ve supply. Power will pass through and be available at the end with the stripe. If you put it the other way around, it will block the current.
What invention in the 1940 was first used in a car using 2 pieces of metal and is rechageable and is now smaller?
the invention was a tri-ode diode which is an electronic gas filled tube with an anode and a cathode and one more switching element. The anode is actually the negative plate and the cathode is the positive side. The third element is a switch for on and off.
