Test a Diode by Digital Multimeter

Forward Biased: When the Positive (Red) test lead is connected to the anode (+) and negative (Black) test lead is connected to the cathode (-) of diode. In Forward-biased, the diode acts like close switch and will pass the current through it like conductors.

Reverse Biased: If we do the reverse as mention above i.e. RED Test lead to cathode (-) and BLACK test lead to the Anode (+) of the diode. In revere-biased, the diode acts like open switch and will not let pass the current through it like resistor.

If multimeter does not show measurements I.e. if multimeter display “OL” reading in both direction (Forward-biased and reverse-biased), its mean diode is dead and acting as an open switch which doesn’t allow current to flow in it.

 

DIY Multimeter Alligator Clip Test Probe Leads

DIY Multimeter Alligator Clip Test Probe Leads

 

OPISOMETER

 

Opisometer an instrument used to measure curved lines on a map.

How is rheostat resistance measured?

Take a multimeter.

Tap the Terminal B and Terminal C and hold properly.

You get the resistance of the sliding contact.

Using DIY Multimeter Alligator Clip

 

Measure Resistance with a Digital Multimeter

Vintage Resistance Coils

Wire-wound resistors are made by having a metal wire wound round a non conductive core. Each end of the wire is then attached to terminals on either side of the core. The wire is typically protected by a layer of paint or other material to form a hard, protective surface.