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常用电子 / 电工 / 传感器 / Thermal Design / Mechanics / Thermodynamics / 电磁学Calculate工具
191电子 / 电工 / 嵌入式 / 传感器 / Thermal Design / Mechanics / Thermodynamics / 电磁学High频Calculate器，SVG 图示Calculate模型，填参数即时出结果：Resistance分压、DC-DC 反馈Resistance、TL431 反馈（Flyback / Forward）、PCB 阻抗 / 载流、CAN bits定时、CRC check、4-20mA、NTC / PT100、PLC 模拟量、散热器选型、Battery stringandCharge、Sallen-Key 滤波器、传输线延时、VSWR、motor选型、线路voltage drop、calorie诺效率……
Protocols & Debugging
6 toolsCAN / CAN FD Bit Timing Calculator
Work out BRP, tq per bit, sample point and segment split from the CAN clock and target bitrate, plus the real bitrate error — before you touch the BTR registers.
Bitrate = f_clk / [BRP × (1 + tseg1 + tseg2)]RS-485 Termination & Bias Resistor Calculator
From node count and unit loads, compute the parallel termination, fail-safe bias resistors, bias current and the maximum line length for the bitrate — the first thing to check when an idle bus drifts or frames go missing.
V_AB = Vcc·Rp/(2Rb + Rp) ⇒ Rb = (Vcc·Rp/V_AB − Rp)/2CRC / LRC / Checksum Calculator
Paste a hex frame and get CRC16 (MODBUS / CCITT / XMODEM / IBM), CRC8, CRC32, LRC, XOR and sum checks, with the checksum bytes appended to the frame.
CRC-16/MODBUS: init FFFF, reflected polynomial A001, low byte firstHEX ⇄ ASCII ⇄ Decimal Converter
Convert between hex frames, text and decimal bytes, with byte count and non-printable characters — the most common first step in serial protocol debugging.
ASCII code = byte value; hex uses two digits per byte, 0x41 = "A"I²C Pull-up & Bus Rise Time Checker
Check whether the rise time from pull-up and bus capacitance meets the I²C spec, and back out the maximum capacitance and pull-up current — for when the waveform will not climb.
t_r ≈ 0.8473·R_p·C_bus (30%→70% of Vdd)SPI Clock & Timing Margin Checker
From slave setup/hold times and round-trip delay, check whether the current SCLK still keeps timing margin and derive the highest usable clock.
T_SCLK ≥ t_SU + t_H + t_PD (round trip)