Hello,
Can the "resistive" portion of a rectifier diode (forward voltage drop / current) be used to model a RC low pass filter ?
Is a rectifier diode component typically noisy ?
I have a LT1083 regulator (DC input) which has a few diodes on the PCB (as part of a bridge rectifier) before the main cap. "If" this can effectively constitute a LPF filter, i'll keep it. Else, i'll ditch the diodes and redo the input with wire for more voltage adjustment.
Thanks.
Can the "resistive" portion of a rectifier diode (forward voltage drop / current) be used to model a RC low pass filter ?
Is a rectifier diode component typically noisy ?
I have a LT1083 regulator (DC input) which has a few diodes on the PCB (as part of a bridge rectifier) before the main cap. "If" this can effectively constitute a LPF filter, i'll keep it. Else, i'll ditch the diodes and redo the input with wire for more voltage adjustment.
Thanks.
A schematic would really help to fully answer, but my short answer is no.
The diodes act as a rectifier, converting the input AC to DC for the capacitor to store. The internal resistance of the diodes would contribute very little to the low pass filter action, being swamped by the rectifier action (which prevents current flow in the other direction- a resistor cannot do this).
If you are saying that the input excitation to the front end of the rectifier diodes is already DC, then the function of those diodes is reversed polarity protection: they steer the current appropriately to the capacitor section, so no matter which is positive and negative, the diodes make it right to the circuitry on the back end. Risk would be up to you if you want to get rid of this.
The diodes act as a rectifier, converting the input AC to DC for the capacitor to store. The internal resistance of the diodes would contribute very little to the low pass filter action, being swamped by the rectifier action (which prevents current flow in the other direction- a resistor cannot do this).
If you are saying that the input excitation to the front end of the rectifier diodes is already DC, then the function of those diodes is reversed polarity protection: they steer the current appropriately to the capacitor section, so no matter which is positive and negative, the diodes make it right to the circuitry on the back end. Risk would be up to you if you want to get rid of this.
The forward resistance of a diode is typically quite small, but of course just like any other resistance it will form a low pass filter with any shunt capacitance. How effective this is will depend on what frequencies you wish to filter away.
Forward biased diodes are typically not noisy; they simply have thermal noise due to their resistance.
Forward biased diodes are typically not noisy; they simply have thermal noise due to their resistance.
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