| Using a simple SMS message sent from your GSM phone, two mains powered loads may to be switched on and off independently, or programmed to d...
More about LED (745)
| Here is a random flashing LED circuit which is economical at just 1 mA while using a minimum number of parts. With two spare gates available...
| Unfortunately, these days it is no longer an inordinate luxury to protect your car against break-in and theft. Many car insurance companies...
| You would be forgiven for thinking that a torch is probably the ultimate minimalist circuit: all you need is a battery, switch and bulb and...
| A digital alarm clock which decodes and synchronises itself to the time signal picked up from the Rugby ‘MSF’ transmitter on 60 kHz.This is...
| If you need to drive a number of white LEDs to provide display backlighting or for a white-light torch what’s the best way to configure them...
| In many small battery powered apparatus it is common to have an LED act as a combined indicator for ‘power-on’ and ‘battery state’. The most...
| Most of the analogue audio media, including radio broadcasting, stick within 60 dB dynamic boundaries. This VU Meter was designed to be used...
| The general assumption is that white LEDs operate at a voltage of 3.6 V and a current of 20 mA, which is about right. Lithium Ion cells coin...
| A universal voltage tester should respond to both dc and ac voltages. The usual types with glow-discharge lamps only work with voltages grea...