Electronics: Theoretical concepts

Articles on design techniques and theoretical concepts.

Parallel Capacitors and the effect of Antiresonance (PDF): 2023-01-31
When multiple capacitors are used for decoupling (which is quite common for micro-controllers are FPGAs, for example), must these all have the same value, or is there an advantage in mounting multiple capacitors with different values in parallel? This white paper presents experiments that demonstrate the effect (and magnitude) of antiresonance when mixing capacitor values. It concludes that, as a rule of thumb, you should keep all decoupling capacitors the same.
Interfacing the VS1053 and VS1063 to DACs and SRCs: 2024-12-02
The VS1053 and VS1063 audio decoder chips from VLSI Solutions support I²S output (in addition to analogue audio output). However, the specific I²S format narrows your choice of DAC, SRC or DSP. The simple circuit presented in this application note converts the I²S format from the VS10x3 to 32Fs Right-Justified, which has much wider support by DAC, SRC and DSP chips.
Configuring a micro-controller for low-speed USB communication: 2024-12-02
All device controllers that support full-speed, also support low-speed. This is inherent to the protocol. However, since only few programmers are have knowledge of the USB physical layer (signal levels), and few circuit designers have knowledge of the programming intricacies, low-speed configuration of an USB device is becoming "lost knowledge". This article fills the void.
Candela, Lumen, Lux: the equations: 2019-04-28
There are various measures in use for quantifying the light produced by a light source, such as a LED. This article gives a brief overview of the more important measures and how they relate.
Most recent update: A paragraph on Luminance (measured in Candela per square metre, or "Nits") is included.