Free online calculator
Battery life calculator

Example ≈ 11.33 h (0.4722 days) at 150 mA
— efficiency is entered as a percentage and applied as a fraction.
What you enter
- Capacity
- Current draw
- Usable efficiency (%)
Free online calculator

Example ≈ 11.33 h (0.4722 days) at 150 mA
— efficiency is entered as a percentage and applied as a fraction.
What you enter
Current-sense shunt— but the sense voltage is the real decision, because it alone fixes the heat: , with R cancelling out. 100 mV at 10 A is a full watt no matter which…
DC-DC converterand . Continuous conduction with ideal switches — a real design lands a few percent higher on duty once the switch and diode drops are counted.
Decoupling capacitorA reservoir close to the chip supplies the current the rail cannot deliver fast enough: , and the capacitor's own must stay below or it drops the…
Energy storageCapacitor: — Inductor:
RC snubberTwo-measurement method. You are giving the ring as the scope sees it, then again with a known capacitor clipped across the switch. comes out of the two…
Voltage regulator— the zener must stay reverse-biased with Iz > 0 to regulate.
Zener shunt regulatorA zener holds the output at by swallowing whatever current the load leaves behind, so the series resistor is sized by the worst corner and never by the…
BJT base resistorA transistor used as a switch is not an amplifier — you deliberately throw its gain away. The mistake is dividing the load current by the datasheet hFE:…