PC817B

The PC817B is a widely used optoisolator (optocoupler) that provides electrical isolation between input and output circuits using an infrared LED and a phototransistor.
### Key Features:
- Isolation Voltage: 5 kV (AC, 1 min)
- Current Transfer Ratio (CTR): 50-600% (depends on model)
- Input LED Forward Current (IF): 50 mA (max)
- Output Collector-Emitter Voltage (VCEO): 35 V (max)
- Response Time: ~4 μs
### Applications:
- Signal isolation in power supplies, microcontrollers, and industrial controls
- Noise suppression in digital/analog circuits
- Feedback loops in SMPS (Switched-Mode Power Supplies)
### Advantages:
- Compact DIP-4 package
- High reliability and long lifespan
- Low power consumption
The PC817B is ideal for applications requiring safe, noise-free signal transmission across isolated circuits. Always check datasheet specifications for exact CTR and voltage ratings.

The PC817B is an optocoupler with a phototransistor output. Equivalent alternatives include:
- TLP521-1 (Toshiba)
- CNY17-3 (Vishay)
- SFH618A (Vishay)
- LTV817 (Lite-On)
- EL817 (Everlight)
These offer similar specs (CTR ~50-600%, Vceo 35V). Verify pinout and parameters for exact compatibility.

The PC817B is manufactured by Sharp Corporation, a well-known Japanese electronics company. Sharp, founded in 1912, specializes in optoelectronics, displays, and consumer electronics. The PC817B is an optoisolator (optocoupler), a device used for signal isolation in circuits, leveraging Sharp's expertise in optoelectronic components. The company is recognized for innovation in LCD technology and solar cells, alongside its broad semiconductor and component portfolio.

The PC817B is a widely used photocoupler (optoisolator) with key applications in:
1. Signal Isolation – Isolates high/low voltage circuits in power supplies, PLCs, and industrial controls.
2. Noise Suppression – Reduces EMI in communication interfaces (RS-232, USB, etc.).
3. Feedback Circuits – Provides voltage feedback in switch-mode power supplies (SMPS).
4. Digital Logic Isolation – Interfaces microcontrollers with relays, motors, or other high-voltage devices.
5. Home Appliances & Automotive – Ensures safe signal transmission in smart devices and automotive electronics.
Its compact design, high isolation voltage (5kV), and reliability make it ideal for safety-critical systems.

The PC817B is available in a DIP-4 (Dual In-line Package, 4-pin) through-hole package. It's a compact, industry-standard optocoupler with a molded plastic body, suitable for PCB mounting. Common variants include lead (Pb) and lead-free (RoHS-compliant) options. The package dimensions are typically 6.5mm × 7.5mm × 3.2mm.