Hello everyone, I recently built a small distribution board to distribute 5V to multiple components for use in a robotics project. I made each output switchable with an individual switch and an LED to indicate the current state. When I went to test it using a lab power supply I noticed that the LEDs would start flickering weirdly when I turned them off and on again.
As it turns out, the LEDs, which I found in my dads old parts in a bag labeled TLBO 5410, are apparently blinking LEDs. I found a datasheet for TLBR5410 LEDs which seem pretty much identical to what I have accidentally used.
Apparently these LEDs are made to operate directly from a 5V supply without an additional current limiting resistor (it is already built in) and are made to continuously blink at a frequency of 3Hz.
Because I thought I was using standard LEDs I added a series resistor causing them to behave weirdly due to low voltage. For comparison, this is how they are supposed to act: https://imgur.com/a/fXlcEDs
There are also LEDs with a built-in “candle flicker” effect. This teardown shows how it’s done with two dies integrate into the LED package: the LED and an ASIC. They also demo a circuit using a small flicker LED and an amplifier to control a much larger LED.
Is it true, or just a myth, that some of those cheap plastic votive candlelights actually use the same IC/circuit as musical greeting cards in order to flicker (that is, they’re ‘playing’ some song to the LED instead of a speaker)? I forget where I heard that but thought it was a clever hack if true.
Lol, awesome. An “entertaining mistake”.
Though I’m sure at the time there was a little annoyance.
Neat, thanks for the post, a great reminder to verify stuff.
