wizard
Member
Hello,
I am a newbie here.
I have a BIG problem understanding ohm's law for a crystal earphone and hope to get a complete response from you guys to solve my problem.
Maybe you guys know that a crystal earphone has very large impedance compared to common ones. That means you will have a sound even if you rub the connected wires too. When the wires are rubbed together there is a very low current in the wires which causes the crystal earphone to vibrate. According to ohm's law I=V/R We know that the above formula is correct for impedance too. So we have a very high impedance say 2Mohm, so can we say that we have to have a very low voltage at the ends of the wires to have a vibration? That means when we rub the wires there is a very low voltage (caused by rubbing the wires together) which causes a very low current in the ends of the wires? If so, how those very low current and voltage are able to cause the HIGH IMPEDANCE crystal earphone to vibrate? Even if we replace the crystal earphone with a very high resistor and feed the resistor with a low voltage source then nearly no or too low current will pass through the resistor and it is too small to do any work.
I am getting confused with this issue!
I am a newbie here.
I have a BIG problem understanding ohm's law for a crystal earphone and hope to get a complete response from you guys to solve my problem.
Maybe you guys know that a crystal earphone has very large impedance compared to common ones. That means you will have a sound even if you rub the connected wires too. When the wires are rubbed together there is a very low current in the wires which causes the crystal earphone to vibrate. According to ohm's law I=V/R We know that the above formula is correct for impedance too. So we have a very high impedance say 2Mohm, so can we say that we have to have a very low voltage at the ends of the wires to have a vibration? That means when we rub the wires there is a very low voltage (caused by rubbing the wires together) which causes a very low current in the ends of the wires? If so, how those very low current and voltage are able to cause the HIGH IMPEDANCE crystal earphone to vibrate? Even if we replace the crystal earphone with a very high resistor and feed the resistor with a low voltage source then nearly no or too low current will pass through the resistor and it is too small to do any work.
I am getting confused with this issue!
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