LED 'smoothing' question

Well...it's not basic but I used a PIC microcontroller to solve that problem. D from BC

To add - this would need to be something connected directly to the bulb, or between the bulb and the voltage going to it, I can't modify the circuitry that's sending the power to the bulbs.

I did the same thing with the MSP430, resulting in an aircraft beacon type light that blinks "softly". It can also be done with a cap but since the LED is basically a current driven device with a (somewhat) fixed voltage across it the cap would have to be larger than with a bulb of same current level. However, one has to carefully check whether the electronics can drive such a concoction. Opamps can oscillate, other stuff could fry when it sees a huge capacitive load.

Do you know what kind of circuitry that is? Reason I ask is that it might not like a capacitive load.

The electronic pinballs & such that I used to fix used SCRs and half-wave rectified AC. To turn the light on, you'd bias the SCR's gate, to turn it off, you'd ground the gate.

So I don't think an LED circuit would hurt it - what I'd try is replace the dropping resistor with two of half the value, in series, with a cap from the junction to power return.

Have Fun! Rich

Nothing to do with the OQ, but I wouldn't "softly" blink an aircraft beacon - I'd use strobes, because they're so much better at catching your eye in your peripheral vision.

Cheers! Rich

AFAIU he wants to smooth the flicker when the drive is PWM'ed. If it's a SCR as you said maybe they do that by skipping half-waves unless it's a dimmer circuit. A SCR might not like the current spikes a "smoothing cap" causes. It probably depends how much margin it has. Worst case there could be a loud pop and whiff of smoke.

On many aircraft you have both types. Soft blink is also needed for obstruction lighting where you are often not allowed to strobe. You'll see that on some of the radio towers, for example.

I definitely don't want to have a risk of damaging the circuitry, this pinball is not cheap and this isn't really some big problem, just makes the leds stand out when they are being pulsed so they are noticeable as being leds. I wouldn't mind trying it on one of my older pinballs but none of them do this pulsing, only my very new (and expensive) ones do. You are correct they are just powered by a transistor either on or off. They are slowly strobed by turning on and off and changing the length of each pulse. I wouldn't have any idea of what cap or resistor values to use for this app.

You'd have to experiment. Some data would help, like voltage and wattage of the lamp that was in there before, and the peak current of the new LED. The resistor in front of the LED works to protect the circuitry but only if the lamp voltage had been much higher than the LED voltage.

The cap would have to be experimented with. Make it as large as it takes to remove the flicker. But have others look at it, too, because one person might see flicker that others don't.

If the lamp voltage had been so high that the resistor has to drop several volts life gets easier: Then you can use two resistors in series and tap off for the cap in the middle. -> Smaller cap.