led array

Three Hour Timer

Manufacturers of cordless drills generally recommend a battery charging time of three hours. Once the charging time is up the battery must be disconnected from the charger: if you forget to do this there is a danger of overcharging the battery. This circuit, which sits between the charger circuit and its battery socket, prevents that […]

Lambda Probe Readout For Carburettor Tuning

A lambda probe (or oxygen sensor) can be found on the exhaust system of most cars running on unleaded fuel. Having reached its normal operating temperature (of about 600 degrees Celsius!) the lambda probe supplies an output voltage proportional to the amount of residual oxygen measured in the exhaust gas. This information is indicative of, […]

Multiple Continuity Tester

The continuity tester is a handy adjunct to an ohmmeter. The unit or component whose continuity is to be checked is connected between terminals E1 and E2 (which may be probes or croc clips). The test current then flowing through the unit/component on test causes a potential drop across resistor R2, which is applied to […]

Simple Stereo VU Meter

I like to see lights move to music. This project will indicate the volume level of the audio going to your speakers by lighting up LEDS. The LEDS can be any color so mix them up and really make it look good. The input of the circuit is connected to the speaker output of your […]

Hacks and Mods: LED Light Box

For beginners, it is their first project that gives them a boost. And in order to get that, it is always necessary to make sure that the project that you select is really useful. One such project is the RGB light fader. This is quite simple and can be done easily by a beginner. Read […]

LED Volt Meter

Here is a Simple LED Volt meter to Monitor the charge level in Lead Acid Battery or Tubular battery. The terminal voltage of the battery is indicated through a four level LED indicators. The nominal terminal voltage of a Lead Acid battery is 13.8 volts and that of a Tubular battery is 14.8 volts when […]

LED Mood Light

Introduction: This circuit makes a nice lamp that consumes little power, runs cool, and has an incredibly long lifetime. The lamp puts out a warm yellow shade of light, the color may be adjusted by changing the number of red or green LED strings. Specifications: Operating Voltage: 12V DC Operating Current: 80ma approx. Theory: The […]

LED Lighting For Dual-Filament Lamps

Before we describe how it’s done, note that we recommend that the result be checked as having sufficient brightness for a stop & tail-light application. That’s because the light output may be inadequate, depending on the tail-light lens and reflector assembly – so use any modified lamps with discretion! As shown, an additional diode (D1) […]

Use an LED Matrix Horizontally

LEDs provide a convenient way to electronically display information. Although the seven-segment LED display, arranged in the form of the digit 8, is common, it does not allow the display of some alphanumeric characters. A 5×7 LED matrix allows the display of all ASCII characters, as well as graphics shapes. The circuit in this Design […]

Police Lights an LED Project

This circuit uses a 555 timer which is setup to both run in an astable operating mode. This generates a continuous output via Pin 3 in the form of a square wave. When the timer’s output changes to a high state this triggers the a cycle on the 4017 4017 decade counter telling it to […]