Circuits by Tomi

Digital audio isolation

Isolator for digital audio is needed in cases where coaxial S/PDIF digital audio link forms a ground loop in your audio system. Typically in coaxial S/PDIF connections the coaxial cable shield is connected to equipment cases. This arrangement easily creates ground loops which can cause noise problems in various places in audio system. A suitable

Build video isolator

Video isolation transformers are primarily used in CCTV application in fields of security, manufacturing, avionics and display. The video isolation transformer is an extremely broad bandpass 1:1 isolation transformer. Its hum isolation is very good and it can sustain very high noise voltages without degradation. Isolation decreases with increasing noise frequency. Video signals can transformer

Scene Quiz Show lights

Assembly TV broadcasts TV program from Assembly computer festival starting Thursday 6. August 2009 in many channels (Internet, cable TV, DVB-H mobile television, 3G mobile video etc.). The broadcast has for many years contained Scene Quiz Show (the name has varied somewhat over years). It involves three contestants answering questions related to the event, demoscene

Use an old Nokia charger to power 1W LED

Here is one useful trick I invented when looking around the transformers/power supplies I had. NOKIA ACP-7 Europe Standard Charger (Original) has a specification of 230 V, 50 Hz, 4.8 VA. Output 3.7 V, 355 mA. A normal 1W white LED is driven with 350 mA maximum continuous current and typically 3-3.8V voltage drop over