4 ms·
How is alternating current steady when varies in magnitude? There is no current flowing on a zero crossing, there is a reason AC and radio use RMS current, are
by SigmundA 5y ago
How is alternating current steady when varies in magnitude? There is no current flowing on a zero crossing, there is a reason AC and radio use RMS current, are you sure you know what your talking about?
Incidentally the ADC's that sample the input dissipate the electrical energy captured by the antenna as heat however little it may be as is the case with all electrical circuits that sink electrical energy. So yes your cellphone does use a "heating effect" because where else does the energy go? Do you think it charges the battery or emits light with the captured energy?
- ncmncm 5y agoAll energy, no matter where absorbed, ends up as heat. So, the heat is meaningless to talk about unless you are making popcorn. It is not the heat, at the end, that makes your phone work. You may read up on how antennas work, if you care to have any actual, you know, facts. I promise it won't say one word about heat.
- SigmundA 5y agoNo the ADC use resistors to measure voltage, resistors turn electric energy into thermal energy, they literally use how much time it takes to dissipate electricity as heat to measure voltage. I know someone who needs to read up on antennas and digital receivers and its not me.
- ncmncm 5y ago
- gus_massa 5y ago> they literally use how much time it takes to dissipate electricity as heat to measure voltage. I never heard that, and looking at the list in https://en.wikipedia.org/wiki/Analog-to-digital_converter#Types https://en.wikipedia.org/wiki/Analog-to-digital_converter#Ty... I can't find any that work this way.
- ncmncm 5y agoRight, none has ever worked that way. Radio receivers do not depend on an analog to digital converter, or even a resistor, to extract a signal from an antenna. The essential component is a diode. (That is not to say that, having detected, amplified, and demodulated an antenna signal, the result won't finally drive an A/D converter; you can drive anything you want to after all that. Even a speaker. But operation of the speaker, too, does not depend in any way on heat.)
- SigmundA 5y agoDigital receivers which are in cellphones are most certainly based on A/D convertors which is what you originally referenced. All captured antenna energy is dissipated as heat through resistance in order to extract useful information and convert it into the digital domain. Even in a analog receiver the power amplifiers used to drive a speaker or whatever are going to dissipate the signals power as heat in order to modulate the amplifiers output power (out power will always be less than power supply power). If you are talking about a crystal radio, then yes the input power drives a speaker and is turned into sound instead (along with some power lost heat in the circuits resistance).