I describe the design and breadboard construction of a visible light probe for an oscilloscope that is useful for measuring light waveforms such as flicker from LEDs, florescent, and incandescent lights. It can measure fast switching light waveforms from LED lights and photo strobes (flashes). It as also useful for measuring the output waveforms of infrared remote controls.
I go over my initial design specifications, how I chose the key components, and the details of how the circuit works. I go over the input offset sampling noise of zero-drift operational amplifiers (op-amps) and show how that effects circuit performance.
I demonstrate measurement of the fast switching light waveform from an underwater flashlight, the measurement of a IR remote control, and the flicker waveforms from a LED and florescent light.
You can download a copy of the slides here: chrisgrossman.com/yt/0008/0008...
0:00 Introduction
0:04 My motivation for designing the visible light oscilloscope probe
0:52 Visible Light Oscilloscope Probe Design Goals
2:20 Osram SFH 3310 Phototransistor Optical Response Specifications
4:56 1. Light Oscilloscope Probe
6:49 Visible Light Oscilloscope Probe Schematic Diagram
10:20 Driving a 50 Ohm Output Load
18:37 offset-correction sampling noise
22:39 Kraken Sports NR-1200 Underwater Flashlight light waveforms at medium output brightness
26:42 2-pole low-pass filter
27:13 Flicker from my Braun LED Shop Light
27:33 Flicker from a fluorescent magnifying lamp with simple inductive ballast
28:20 Visible Light Oscilloscope Probe Conclusion