Capacitance needed to stabilize a voltage pulse

[Daniel Floyd]

ok i need to know the value of the capacitor which i need.

i have a pulse voltage of 6mV which i want to stabilise to create a voltage which will power a small L.E.D. i currently have a bridge rectifier and i know i need a capacitor but what would the value of this capacitor be.

 

[davenn]

6mV isn't going to power a LED... LED's are current driven ... ie. you need a constant current at a given voltage the common 5mm diameter LEDs require ~ 20mA

you had better expand a bit on where your 6mV is coming from
you are really going to need a few volts or so

Dave

 

[berkeman]

ok i need to know the value of the capacitor which i need.

i have a pulse voltage of 6mV which i want to stabilise to create a voltage which will power a small L.E.D. i currently have a bridge rectifier and i know i need a capacitor but what would the value of this capacitor be.

Maybe he means 6V pulse like in his old thread?

https://www.physicsforums.com/showthread.php?t=622069

.

 

[davenn]

Maybe he means 6V pulse like in his old thread?

https://www.physicsforums.com/showthread.php?t=622069

.

ahhhhhh wasnt immediately aware of that one

its really frustrating when people continuously start new threads on the same topic

Dave

 

[alphysicist]

The capacitance needed to stabilize a voltage pulse depends on several factors such as the frequency and duration of the pulse, the load resistance, and the desired level of stabilization. In order to determine the appropriate value of the capacitor, it is important to calculate the time constant of the circuit, which is the product of the capacitance and the load resistance. This time constant should be at least 5 times larger than the duration of the pulse in order to effectively stabilize the voltage.

For a pulse voltage of 6mV and an LED load, a small value capacitor in the range of microfarads (µF) or even picofarads (pF) may be sufficient. However, it is recommended to perform further calculations or simulations to determine the exact value of the capacitor needed for your specific circuit.

Additionally, the type and quality of the capacitor can also affect its performance in stabilizing the voltage pulse. It is important to choose a capacitor with low equivalent series resistance (ESR) and high capacitance stability to ensure proper stabilization.

In conclusion, the value of the capacitor needed to stabilize a voltage pulse depends on various factors and should be carefully calculated or simulated to ensure optimal performance in powering your LED.