Archives pour 06/2017

People or Object counter Circuit diagram using IC 555 and IC 4026

26/06/2017 Comments off

People / Object counter circuit have a wide variety of applications in Banks, Hospitals, factories etc. This project focuses on building an effective counter using IR as a sensing element and capable of counting from 0 to 999. This project uses Two simple IC’s ( IC 555 & IC 4026 ) with IR transmitter and Receiver to detect the incoming people/object.

This Project comprises of Three parts

  1. IR Transmitter
  2. IR Receiver
  3. 7 Segment drivers


Freq = 1.45 / ( R3 + 2R1 ) C2IR transmitter was wired around Astable multivibrator using IC 555. As we all know that multivibrator produce square wave pulses and we gotta fix the frequency of the output signal as 38 Khz since we are about to use TSOP 1738 an Infra red sensor which is capable of detecting signals of 38 Khz. The frequency of the astable depends on R1,R3 and C2. So lets do some math

         = 1.45 / (470 + 2 * 1690 ) * 100 * 10

         = 37.6 Khz

So we have fixed the IR frequency of 38 Khz and now Transmitter part is done.

Please note that i have used a simple IR transceiver module (brown board  – right top) for this project to make things simple. You can use use IR module like i did if you have any. If not build the IR transmitter using IC 555 as shown in above circuit. The receiver part was given in the below circuit diagram.

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Categories: Électronique, Matériel Tags:

Residual-current device

21/06/2017 Comments off
From Wikipedia, the free encyclopedia

An RCD does not provide protection against unexpected or dangerously high current (called spikes or surges) when current is flowing in the usual wires in the circuit, therefore it cannot replace a fuse or protect against overheating or fire risk due to overcurrent (overload) or short circuits if the fault does not lead to current leakage. Therefore, RCDs are often used or integrated as a single product along with some kind of circuit breaker, such as a fuse or miniature circuit breaker (MCB), which adds protection in the event of excessive current in the circuit (the resulting RCD with overcurrent protection called an RCBO). RCDs also cannot detect the situation where a human accidentally touches both conductors at the same time, since the flow of current through an expected device, an unexpected route, or a human, are indistinguishable if the current returns through the expected conductor.

RCDs are usually testable and resettable devices. Commonly they include a button that when pressed, safely creates a small leakage condition, and a switch that reconnects the conductors when a fault condition has been cleared. Depending upon their design, some RCDs disconnect both the energized and return conductors upon a fault, while others only disconnect the energized conductor and rely upon the return conductor being at ground (earth) potential. The former are commonly known as “double-pole” designs; the latter as “single-pole” designs. If the fault has left the return wire “floating” or not at its expected ground potential for any reason, then a single-pole RCD will leave this conductor still connected to the circuit when it detects the fault.

[one-third-first]A two-pole, or double-pole, residual-current device. The test button and connect/disconnect switch are colored blue. A fault will trigger the switch to its down (off) position, which in this device would disconnect both conductors.[/one-third-first]

  • Log-log graph of the effect of alternating current I of duration Tpassing from left hand to feet as defined in IEC publication 60479-1.[1]


1: Electromagnet with help electronics
2: Current transformer secondary winding
3: Transformer core
4: Test push-button
L: Line conductor
N: Neutral conductor


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