Electronics handbook

Handbook — type in the search box (every word must match a title, tag or formula) or pick a category: Formulas, Tables, Pinouts, Guides. Each formula has a calculator: values take engineering suffixes (4k7, 100n, 2.2µ, 10m), and what you type is remembered. Every entry has a Link button that copies a deep link to it (?e=<entry>).

MOSFET / BJT switch — a hard-switched MOSFET: gate currents from the driver voltage, Miller plateau and gate resistance; transition times from Qgs2 + Qgd; gate-drive power; conduction loss with RDS(on) rising with temperature; switching, output-capacitance and reverse-recovery losses; the junction temperature through θJC, θCS and θSA (solved iteratively); the heatsink you’d need. Enter the datasheet’s safe-operating-area line as V, A pairs to check an operating point (log–log interpolation, derated to the case temperature). A BJT switch section sizes the base current and resistor for a forced β.

Tables against their sources: NEC 310.16 (12 AWG 20/25/30 A, 4/0 195/230/260 A) and 240.4(D); IPC-2221B Table 6-1 rows (48 V external uncoated 0.6 mm; 325 V peak 2.5 mm; per-volt rule above 500 V); the IPC-2221 equation (1 A, 1 oz external, 10 °C → 12 mil); AWG diameters and resistance (12 AWG 2.053 mm, 5.21 mΩ/m); E-series sizes including E192’s 9.20 exception.

Formulas: the NE555 datasheet’s 1.44/((R₁ + 2R₂)C), Butterworth Sallen–Key Q = 0.707, ~60 mV per decade for an ideal diode at 300 K, copper skin depth 8.5 mm at 60 Hz and 66 µm at 1 MHz.

Switch calculator against app notes: Microchip AN786 (50 nC in 25 ns needs 2.0 A); TI SLPA009A Tables 2 and 3 (gate-drive losses 0.02 W and 0.04 W, Qrr loss 0.20 W, conventional switching loss 0.41 W — the note doesn’t give the driver’s resistance; 1 Ω reproduces its figure).

Rules of thumb are labelled as such; NEC and IPC tables are summaries — use the standard itself (and your local code) for anything that matters. Mains clearances are set by product safety standards (IEC 62368-1, UL), not IPC-2221.

IPC-2221’s trace current is a 1950s curve fit; IPC-2152 is more accurate but chart-based.

The MOSFET model is first-order hard switching: no common-source inductance, ringing, or soft switching; datasheet charges are at specific conditions. The SOA check can’t capture linear-mode instability in modern trench MOSFETs.

Pinouts are the common parts' standard pinouts — always check the datasheet of the part you actually have (some second sources and SMD variants differ).