Op-Amps & Analog
Every op-amps & analog 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.
6 calculators in this section
- BJT as a Switch Calculator (Base Resistor)Base resistor for an NPN transistor switching a lamp, relay or motor from a microcontroller pin — with the overdrive factor that keeps it saturated, the nearest standard value rounded down, and a check that the pin can supply the base current.
- BJT Biasing Calculator (Voltage-Divider Bias)The four-resistor bias that every small-signal transistor stage is built on: divider, emitter and collector resistors to an operating point, the voltage gain and impedances that follow from it, and the number that justifies the whole topology — how far the collector current moves when β doubles. Design mode goes the other way, from a target IC and VCE to four E24 resistors.
- Comparator Hysteresis (Schmitt Trigger) CalculatorUpper and lower switching thresholds, hysteresis width and centre for a comparator with positive feedback — inverting or non-inverting, push-pull or open-drain — plus a design mode that picks the resistors for the thresholds you want.
- Op-Amp Capacitive Load Stability CalculatorWhy a buffer oscillates when you put a cable on it: the amplifier's open-loop output resistance and your load capacitance make a pole inside the feedback loop. Get the frequency of that pole, the phase margin left, the overshoot and ringing that follow, the largest capacitance stable at your gain, and the isolation resistor that fixes it — with what the resistor costs.
- Op-Amp Inverting Amplifier CalculatorGain, gain in decibels and output voltage of an inverting op-amp stage, whether the output clips against your supply rails, the input impedance it presents — and standard resistor pairs for a target gain.
- Op-Amp Non-Inverting Amplifier CalculatorGain 1 + Rf/R1, gain in decibels, output voltage and rail clipping for a non-inverting op-amp stage — plus the two speed limits that catch beginners out: closed-loop bandwidth and full-power bandwidth.