Timer Controller | Electronic Project Circuits

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Timer control 1-15 minutes by Triac 2N6075 and LM555-LM358

Most timer circuits. Often used with electrical transformers containing low as 9V and 12V, and use of electrical control relays.but the 1-15 minute timer circuit.It uses a triac instead of electrical control.This can be used with a 220V power house it is not connected to the transformer. Make smaller and easy to use.
This circuit is divided into three parts: work special high-voltage level, the scheduling and control electrical appliances.
When 220V power supply circuit R1, C1 and ZD1 a special level voltage 220V to rest 10V. The 10V input voltage is power supply to IC1 No. 555. which is part timer.Which is set by R3 and C3 at a specified time period you want.Thus, when switch S1 (Start) IC1 work out a pulse signal generator via the output pin 3 of IC1.The VR1 function timer from 1-15 minutes. Then sent into the period to pin 2 of IC2 number LM358. Which is controlled electrical appliances. The output of IC2 to expand a pin 1 with a voltage of about 5V. to stimulate the pin to the gate (G) of a Triac T1. which a triac acts as a switch on and off electrical appliances.When pressure on the to stimulate pin G a Triac will conduct between MT1 and MT2 pins result appliances are working fluorescent light. And after the set time-out quits and IC2 to stop the flow with the Triac. Which IC2 stopped work, simply hit the switch S2 to reset or unplug any.

Be the first to comment - What do you think? Posted by admin - February 21, 2011 at 11:37 pm

Categories: Electronic Control, Timer Tags: timer controller, triac control circuit

An Accurate Reaction Timer

Add a cheap stopwatch to this circuit to produce an accurate reaction timer. The circuit is wired in parallel with the start/stop button in the watch via a 2.5mm socket, which fits snugly in one corner of the casing. The person conducting the test (the “tester”) resets the stopwatch and turns on the reaction timer’s power switch (S3). The person being tested (the “subject”) places his or her fingers near the “STOP” push-button switch (S4). Next, the tester covertly sets a delay time with VR1 and selects either the LED or buzzer alarm via S2. To initiate the sequence, the tester then presses the “START” switch (S1). This triggers 555 timer IC1, which is wired as a monostable. Its output (pin 3) goes high for 2-12 seconds as determined by the setting of VR1. At the end of this delay pin 3 goes low and triggers IC2, another 555 timer in monostable mode.
The output from IC2 (pin 3) activates the alarm (buzzer or LED) for about 0.5s. After inversion by Q1, it also triggers IC3, another 555 monostable. The positive pulse from IC3 turns on Q2, briefly closing the start/stop switch circuit in the watch. The watch starts to count up. After a short period, the subject reacts to the alarm and pushes the “STOP” button (S4), freezing the stopwatch. The reaction time can then be read off with 1/100th of a second accuracy. Comparative reaction times could be measured when a subject is: rested or tired, silent or talking, before or after a night out, using a mobile phone, etc. For motoring realism, rig up dummy accelerator and brake pedals, with the brake switch making the stop contact. Or take it to your club and test people as they enter and after they’ve been “steadying their nerves” at the bar.
Author: A. J. Lowe – Copyright: Silicon Chip Electronics

Be the first to comment - What do you think? Posted by admin - October 23, 2010 at 10:37 pm

Categories: Timer Tags: accurate reaction timer, timer controller

Electronic Time Constant Control

These circuits show methods of changing the operating frequency of astable LM555 timers electronically. Any source that can drive the base of transistor Q1 can control these circuits.
The advantage of using this type of frequency control is that the duty cycle of the timer is not affected when the frequency is changed. [...]
Read more Source: http://home.cogeco.ca/~rpaisley4/LM555.html