Loaded Voltage Divider & E-Series Resistor Calculator
Calculate exact loaded output voltage, Thevenin equivalent resistance (Rth) and voltage (Vth), loading error percentage, resistor power dissipation, and closest standard EIA E12/E24/E96 resistor pairs.
Circuit Parameters & Load
V
V
Used for standard E-series suggestions.
ADC input impedance, microcontroller pin, or base.
Divider Analysis & Loading
ANALYZED
Loaded Vout (Actual)
3.333 V
Unloaded: 5.000 V
Loading Error
-33.3 %
Voltage drop from load
Thevenin Resistance (Rth)
5.00 kΩ
Output source impedance
Quiescent Current (Iq)
0.667 mA
Total current drawn
Resistor Power Dissipation
Power in R1:
4.44 mW
Power in R2:
1.11 mW
Standard 0603 (100mW) or 0805 (125mW) resistors have ample thermal safety margin.
Closest Standard E-Series Pair
E24 Match
Recommended R1:
20 kΩ
Recommended R2:
10 kΩ
Achieved Vout:
3.333 V
Formulas & Loading Principle:
• Effective lower leg: (R_{2, ext{eff}} = rac{R_2 cdot R_L}{R_2 + R_L})
• Loaded output: (V_{ ext{out}} = V_{ ext{in}} cdot rac{R_{2, ext{eff}}}{R_1 + R_{2, ext{eff}}})
• Thevenin equivalent: (V_{ ext{th}} = V_{ ext{in}} cdot rac{R_2}{R_1 + R_2}), (R_{ ext{th}} = rac{R_1 cdot R_2}{R_1 + R_2})