How many different conditions do you reckon may be signalled with just one LED Two, maybe three Using this simple circuit, a lot more! Admittedly, a two-colour LED is used here. Such a device consists of two light-emitting chips, usually red and green, encapsulated in the same case. It has three pins: two for the anodes, and one for the common c
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athode. In this way, each diode can be activated separately. Various mixed colours may be obtained by varying the current through the two diodes. At least four discrete colours are then easily perceived: pure red, pure green, orange (IR ‰ 2IG) and yellow (IG ‰ 2IR). In the present circuit, the LED elements are driven by CMOS three-state buffers type 4503, which, unlike most CMOS ICs from the 4000 series, are capable of supplying up to 10 mA of output current. The LED currents are limited by resistors R1 through R6, whose values invite experiments with brightness and colours according to your own taste. The circuit was originally developed to indicate the state of three inputs, a, b, and c (non-binary, i. e. , only one of these is at 1 at any time), with the configuration (a=b=c=0) representing the fourth state. The latter is decoded by NAND gate IC1. An additional effect is produced by gates IC1a and IC1b, which are connected up into an oscillator circuit producing approximately two pulses per second. These pulses are used to control the common-enable input, DA (pin 1) of the 4503, so as to produce a flickering effect. The oscillator is controlled by means of inputs d` and e`. Pulling both of these logic high disables the oscillator and the LED driver. With e=0 and d=1 the outputs of the 4503 are switched to three-state, and the circuit is in power-down standby mode. Although designed for a 12-V supply voltage, the circuit...
This project fits more for custom made battery casing that can have more space to hide things inside. This switch with few alterations can be used for any other project as well but is designed based on e-bike needs! This project use a clever functionality of....
The circuit described here uses ultrasonic oscillations and operates based on the propagation velocity of these oscillations in the air. Thus, we can easily determine the distance of two points if the time within which the wave travels this distance is....
Sometimes the precious metals are hidden too deep and are not detected except with complicated devices. In many cases, however, small pieces of precious metal buried near the surface can be detected by relatively simple means. Everyone is very attractive to....
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The principle behind a metal detector is really very simple. Proof of this is the circuit that follows, in which it proves that the construction of a metal detector can be done in the minute, with few components that we find very easily everywhere. With the....
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In the past the sounding (sea bottom measurement) was done with the "bullet", that is, with a heavy lead object that the seamen plucked into the sea hung from a calibrated rope. As soon as the "bullet" reached the bottom, the depth appeared directly from the....
This Amplifier was designed to have the following specifications: Distortion less than 0.1% at full power of 100W even at 20KHz. Power has to be attributed to an extended bandwidth. The output transistors must be protected against short circuits. The power....
A series of LEDs serve to alert the gardener when plants need water. Using two conventional digital integrated LEDs and a series of LEDs, we make a very useful device for gardening. The device detects the amount of water in the pot and alerts the grower.....
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