Resistor Divider E96 Calculator

Example Data Table

Formula Used

The basic divider equation is:

Vout = Vin × R2 / (R1 + R2)

When a load is connected, R2 is replaced by its parallel value:

R2 loaded = 1 / ((1 / R2) + (1 / Rload))

The divider current is:

I = Vin / (R1 + R2 loaded)

Voltage error is:

Error % = ((Actual Vout - Target Vout) / Target Vout) × 100

How To Use This Calculator

1. Select a mode for pair search, direct output, or solving R1.
2. Enter the input voltage and target output voltage.
3. Add R1 and R2 when using the output mode.
4. Enter a load resistance when the divider drives a circuit.
5. Choose the E96 decade range for resistor searching.
6. Press calculate to show results above the form.
7. Use CSV or PDF buttons to save the result.

Article: E96 Resistor Divider Design

Purpose

A resistor divider is a simple voltage scaling network. It uses two resistors in series. The output is taken from the center node. Designers use it for references, sensors, level shifting, and measurement inputs. This calculator focuses on E96 values. That series gives many precise choices.

Why E96 Matters

The E96 series contains ninety six preferred values per decade. It is common with one percent resistors. More values mean a closer voltage match. A close match helps when an analog input needs a narrow target. It also reduces trimming during prototypes.

Loaded Output

A divider is not ideal when a load is attached. The load sits in parallel with the lower resistor. This changes the effective lower resistance. The output voltage may drop. High load resistance causes little change. Low load resistance can create large error. Always include the load when it is known.

Power And Current

Divider current affects battery life and heating. Larger resistors save current. Very large resistors can increase noise and input leakage error. Small resistors waste power. A practical design balances accuracy, current, noise, and source limits. The calculator shows current and power, so choices are easier.

Finding Better Pairs

The best pair is not always the smallest error alone. A circuit may need low current. Another circuit may need low source impedance. Review several ranked pairs before selecting a final part. Then check tolerance, temperature drift, and input bias current. These details matter in precision electronics.

Practical Checks

Use real component tolerances in your final review. A one percent pair can still shift the output. For critical work, simulate worst case values. Also confirm resistor voltage ratings. High voltage dividers need safe spacing and rated parts. For normal low voltage projects, the E96 search is usually enough. Save results as CSV or PDF for project notes and reviews.

FAQs

What is an E96 resistor divider?

It is a two resistor voltage divider using values from the E96 preferred number series. These values are common for one percent resistors.

Why use E96 instead of E12?

E96 gives many more values per decade. This allows closer voltage targets and smaller matching error than wider value series.

Which resistor is R1?

R1 is the top resistor connected between input voltage and output node. R2 is connected between output node and ground.

What happens when a load is connected?

The load appears in parallel with R2. This lowers the effective bottom resistance and changes the output voltage.

Can I use this for sensor scaling?

Yes. It is useful for scaling sensor voltage before an analog input, when impedance and input limits are checked.

Does resistor tolerance affect the output?

Yes. Tolerance can move actual resistance away from the nominal value. Precision designs should check worst case limits.

How should I choose decade range?

Select a range that matches your impedance and power goals. Higher values reduce current, while lower values reduce loading sensitivity.

Is divider current important?

Yes. Divider current affects wasted power, battery life, noise behavior, and output stiffness. Review it before selecting parts.