Timers, Oscillators & Digital
Every timers, oscillators & digital calculator on CalcEngines — unit converters, derived indices and interpretive tools, each with its formula, a worked example and the reference intervals it is judged against.
7 calculators in this section
- 555 Timer Astable CalculatorFrequency, period, high and low times and duty cycle for a 555 in astable mode — or work backwards from the frequency and duty you want to R1, R2 and the nearest E12 or E24 parts.
- 555 Timer Monostable (One-Shot) CalculatorPulse width of a 555 one-shot from R and C — or the resistor or capacitor you need for the pulse width you want, rounded to a real E12 or E24 value, with the datasheet's trigger rules.
- Crystal Load Capacitor CalculatorThe two capacitors a Pierce oscillator needs, from the crystal's specified load capacitance and the stray capacitance of your board and the chip's own pins — plus the part nobody prints: how far off frequency the nearest standard value puts you, and whether the oscillator has enough gain to start at all.
- I²C Pull-Up Resistor CalculatorThe window your I²C pull-ups have to sit in: the minimum set by the sink current and Vₒₗ, the maximum set by the rise time your speed mode allows for the bus capacitance you have, a standard value between them, and the rise time and sink current it actually gives — all from NXP UM10204.
- Logic Level Compatibility and Level Shifter CalculatorWhether one device can drive another directly, in both directions, from the four numbers on their datasheets — with the noise margins as the voltages they actually are, the absolute-maximum check that decides it whatever the margins say, and the resistive divider or MOSFET shifter you need when it cannot.
- PWM Duty Cycle and Average Voltage CalculatorOn and off times, average voltage, RMS voltage and average power from a PWM frequency and duty cycle — plus the microcontroller timer view: what frequency and duty-cycle step your clock, prescaler and resolution actually give.
- UART Baud Rate Error CalculatorThe divisor your peripheral clock and target baud rate actually produce, the baud rate that comes back out of it, the error in per cent — and the part that decides whether the link works: how far the sampling point has drifted by the stop bit, and how much error the receiver at the other end can take.