However, based on common optocoupler naming conventions and visual similarities, here are the three most likely components you might be looking for, along with a summary of their datasheets:

Applying those datasheet details, Mara redesigned the input resistor and added a small pull-up on the output so the phototransistor would switch cleanly into the microcontroller’s input. She derated the device for higher temperatures and added a snubber across the motor so voltage spikes wouldn’t exceed the A1458’s isolation rating. On the PCB she followed the recommended clearance distances, and in firmware she added a timeout to detect any stuck output that might indicate LED failure.

Current Transfer Ratio (CTR): This is the ratio of output current to input current. For the A1458, this is generally between 50% and 600%, categorized into different "ranks" (e.g., Rank L, Rank A). Pinout Configuration

Output (Phototransistor) Characteristics

| Parameter | Symbol | Conditions | Min | Typ | Max | Unit | |-----------|--------|-------------|-----|-----|-----|------| | Collector-Electron Breakdown | BV_CEO | I_C = 100 μA, I_F = 0 | 80 | - | - | V | | Emitter-Collector Breakdown | BV_ECO | I_E = 100 μA | 6 | - | - | V | | Dark Current (Leakage) | I_CEO | V_CE = 20V, I_F = 0, Ta=25°C | - | 10 | 100 | nA | | Dark Current at 100°C | I_CEO | V_CE = 20V, I_F = 0, Ta=100°C | - | 1 | 10 | μA |