Voltage Drop Across Resistor Calculator (I x R and Power)
Calculate resistor voltage drop and power dissipation from current and resistance.
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Series and parallel circuit calculators for voltage dividers, resistor networks, LED series resistors, shunts, reactance, capacitors, RC timing, and voltage-drop checks.
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Soft Starter Bypass Calculator
Compare motor running current and a service-factor reference current with an entered soft-starter bypass rating for an early equipment review.
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Sensor Resistor Calculator
Estimate ideal series-resistor headroom, resistance, and dissipation for a defined DC sensor interface.
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Reactance Calculator
Compare XL, XC, and net reactance from entered frequency, inductance, and capacitance for circuit review.
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Motor Control Circuit Calculator
Estimate control-circuit VA, current, reserve requirement, transformer margin, and utilization from entered device loads.
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LED Series Resistor Calculator (DC Supply to Resistor Value)
Estimate the current-limiting resistor for a series LED string and show a rounded-up common-value candidate.
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Impedance Magnitude Calculator
Estimate single-frequency AC impedance magnitude, phase angle, and power-factor magnitude from resistance and net reactance.
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Enclosure Heat Dissipation Calculator
Calculate enclosure temperature rise, internal temperature, and margin from internal heat, ambient temperature, and thermal resistance.
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Current Limiting Resistor Calculator
Calculate DC series resistance, resistor voltage, and resistor power for a target current using entered supply and load voltage.
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Control Circuit Fuse Calculator
Calculate control load current, inrush reference current, and entered fuse-rating margins without selecting or approving a fuse.
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Control Relay Contact Load Calculator
Calculate relay contact VA, utilization, and remaining entered rating from contact voltage, contact current, and VA rating.
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Control Cable Shield Calculator
Calculate control-cable shield loop resistance, voltage drop, and dissipation from entered length, resistance, and current.
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Contactor Coil VA Calculator
Calculate steady-state VA, inrush VA, inrush ratio, and inrush excess for an entered contactor coil.
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24 VDC Control Voltage Drop Calculator
Estimate 24 VDC control-circuit voltage drop, load voltage, and margin against a documented minimum load voltage.
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Thevenin Equivalent Calculator
Enter the Thevenin voltage, Thevenin resistance, and load resistance to evaluate source loading, terminal voltage, and resistive power.
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RL Time Constant Calculator
Enter resistance and inductance to calculate the first-order RL time constant and its five-time-constant settling reference.
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Parallel Resistor Value Calculator
Calculate the equivalent resistance of three fixed resistors in parallel for component-level circuit review. Final component selection still requires rated voltage, power, tolerance, and application checks.
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Resistor Power Rating Calculator
Evaluate resistor dissipation and a preliminary minimum wattage from the entered electrical values. Confirm the exact part's thermal, pulse, and maximum-working-voltage ratings before selection.
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Series Resistor Value Calculator
Calculate the equivalent resistance of three fixed resistors in series for component-level circuit review. Final component selection still requires rated voltage, power, tolerance, and application checks.
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RC Filter Cutoff Calculator
Calculate the ideal first-order RC corner frequency from resistance and capacitance. The result is circuit arithmetic, not a complete filter, EMC, equipment, or code approval.
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PLC I/O Load Calculator
Enter repeatable PLC, I/O, communication, and field-device rows with manufacturer-supplied current data. Backplane and field-power budgets remain separate.
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Maximum Power Transfer Calculator
Evaluates a known Thevenin source against an entered resistive load and separates matched-load power from efficiency and equipment limits.
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4-20 mA Instrumentation Loop Power Calculator
Reduces two-wire 4-20 mA loop supply, burden, wiring, and device data into voltage drop, transmitter margin, allowable resistance, and loop power.
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Inductor Parallel Value Calculator
Combines two or three uncoupled parallel inductors into an ideal equivalent inductance while leaving current sharing and component ratings separate.
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