Tag
precision
4 articles.
- ADC noise floor calculation: SNR, process gain and the FFT
An ideal 12-bit ADC has 74 dB of SNR; its 4096-point FFT shows a floor at 107 dB. Both are right, and the 33 dB between them is the commonest misreading.
- Resistor codes: colour bands, SMD digits and EIA-96
How to read every resistor marking, why the E-series values look arbitrary, and which codes are genuinely ambiguous — with the tolerance derived, not looked up.
- Sallen-Key low-pass filter design, without the guesswork
Pick a response shape, read its Q, and get the two capacitors and one resistor. Then the four things that decide whether the built filter matches the design.
- Guard rings: stopping PCB leakage into high-impedance nodes
Gigaohm trace-to-trace resistance still leaks nanoamps at 5 V. Compute when board leakage beats V_OS and bias current, and lay out a driven guard to remove it.