Clinical thermometer

 

Tapping key

 

a light flexible metallic strip provided with contacts so that when it is momentarily pressed an electric circuit is made or broken and when it is released the opposite effect is automatically produced.

Van de Graaff generator

If we bring the grounding rod close enough to the large sphere, the electrons rip through the air molecules in order to jump onto the grounding rod, creating a spark and crackling noise.

DIY Test tube brushes

DIY test tube brushes using contantant wire S.W.G 22

 

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.