A collection of technical articles that do not fit in any of the other categories.
- Candela, Lumen, Lux: the equations
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.
- Folding large format technical drawings
Technical drawings in A3 or larger formats can be rolled or folded (for archiving or sending by post). This article lists the advantages that folded drawings have —provided that they are folded correctly. Then it presents the procedure to fold large format drawings, from A3 to A1.
- Reel quantity estimate
A simple method to estimate the number of components left on a reel.
- Reflow soldering profiles
With a special focus on the eC-reflow-mate from Eurocircuits, this article delves into the art and craft of creating reflow soldering profiles. Phenomenons like thermal inertia and their effects on the soldering profile.
- Interfacing the VS1053 and VS1063 to DACs and SRCs
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.
- LED current source
This article presents a circuit for a "constant current source", for example to drive LEDs. The circuit allows the current flow to be switched on and off, with 5V TTL-logic. One way to use the on-off switching capability is to dim the LEDs with pulse-width modulation.
- A MIDI to RS232 converter
The MIDI protocol is a serial data communications protocol using on a "current loop" physical layer, and using a Baud rate of 31250 bps. This article shows the electronics needed to convert between current loop and the RS232 signal levels. The circuit can be connected directly to the RS232 port of the H0420 MP3 player. In the second part, the article covers the "software protocol" of MIDI and develops a simple script to send and receive MIDI commands.
- An RS232 "spy" cable
The RS232 norm defines a one-on-one communication link between two devices. With a special cable, though, it is possible to have a third device (a PC) "listen in" on the data —a useful trick in debugging serial protocols or for deciphering an unknown protocol.
- A voltage inverter circuit
Sometimes you need to generate a negative voltage when you only have a positive power supply. The circuit in this application note does just that. The circuit was built to drive LCDs that require a negative LC-driving voltage.