The Calcylator Blog

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Electrical & Engineering guides

30 articles

Electrical & Engineering5 min read
Parallel Resistors: Why Two Equal Values Halve
Two resistors in parallel: R = R1 × R2 ÷ (R1 + R2). Two 100 Ω parts give 50 Ω, and the total is always below the smallest branch.
Electrical & Engineering5 min read
Resistors in Series: Add Them Up, Then Check Voltage
Resistors in series simply add: R(total) = R1 + R2 + R3. Values of 100 Ω, 220 Ω and 330 Ω give 650 Ω and about 18.5 mA from a 12 V supply.
Electrical & Engineering5 min read
Series and Parallel Resistance Formulas
Series resistors add: 100 + 220 + 330 = 650 Ω. In parallel the same three give 56.9 Ω. Formulas, shortcuts and a sanity check for each case.
Electrical & Engineering5 min read
Solar Battery Autonomy: How Many Hours It Lasts
Autonomy = battery kWh × usable fraction × inverter efficiency ÷ load kW. A 10 kWh bank at 80% usable, 90% efficient and 1.2 kW lasts 6 hours.
Electrical & Engineering5 min read
DC-to-AC Ratio and Solar Inverter Clipping
The DC/AC ratio is array kW ÷ inverter kW. A 6 kW array on a 5 kW inverter gives 1.2, so output flattens when the array makes more than 5 kW.
Electrical & Engineering4 min read
Solar Panel Payback Period: A Realistic Estimate
₹3,00,000 net cost and ₹45,000 yearly savings pays back in about 6.7 years on the simple method. See degradation and tariff rises change it to about 6.2.