![]() ![]() Any switching mechanism (which may have its own set of impedances) must be assumed because nothing is specified. If the discharge is repetitive, the circuit response may differ. If the supply voltage is very close to the forward voltage drop of the LED, ESR may be an issue, but that would depend on the capacitance of the storage capacitor and supply resistance. A 1 us draw of charge from a charge storage capacitor is nominal, so the storage capacitor will maintain most of its charge after a single cycle. So unless there is a current limiting resistor in series with the LED, the discharge time constant will be mostly determined by the LED forward voltage and the power supply resistance. The total ESR of two capacitors placed in series is modeled by the parallel resistance equation $$\dfrac$$.īecause a large portion of ESR is lead resistance (the resistance of the lead wire) plus lead-to-plate resistance (the resistance of the lead to plate connection), a well engineered and manufactured capacitor will have much less resistance than the load, as Phil has shown.Or if it's more complex than that.īasically the question comes down to is there any reason why one wouldn't place a ceramic capacitor in parallel with an electrolytic cap to drastically reduce the total ESR. Just wanting to clarify my understanding of ESR here, because I'm not fully sure if it should be modeled the way I would think to model series resistance.
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