Secret Diagram: controlled

Showing posts with label controlled. Show all posts

Wednesday, 8 March 2017

Simple Cell Phone Controlled Audio Video Mute Switch

This is a project of simple circuit of the cell phone-controlled audio/video mute switch. This cell-phone-controlled audio/ video mute switch is highly useful in automobiles. The circuit automatically disconnects power supply to the audio/video system whenever the mobile handset is lifted off the holder for making or receiving a call. You can use any readily available cell-phone holder with some mi-nor alterations or fabricate it yourself as shown in Fig. 1.

Fig. 1: Proposed cell-phone holder

The circuit is wired around IC LM555 (IC1), the CMOS version of timer NE555, as shown in Fig. 2. IC1 is used as a medium current line driver with either an inverting or non-inverting output. It can sink (or source) current of up to 50 mA only, so take care while handling it. The audio/video system is connected to the circuit via normally opened (N/O) contacts of the relay.

Fig. 2: The circuit of the cell phone-controlled audio/video mute switch

When the cell phone is in its holder, LDR1 does not receive any light from white LED1 and its resistance is high. As a result, the voltage at pin 2 of IC1 re-mains high to provide a low output at pin 3. The low output of IC1 activates relay RL1 and the audio/video system gets power supply via its N/O contacts. LED3 glows to indicate that the audio/video system is ‘on.’ When the handset is taken off the holder, light rays from LED1 fall on LDR1 and its resistance decreases. As a result, the voltage at pin 2 of IC1 de-creases to provide a high output at its pin 3. The high output of IC1 deactivates relay RL1 and the audio/video system does not get power supply. LED2 glows to indicate that the audio/video system is ‘off.’ Preset VR1 is used to control the sensitivity of the circuit. Zener diode ZD1 is used for protecting white LED1 from the higher voltage. The circuit works off a 12V car battery. Switch S1 can be used to manually switch on/off the audio/video system.

Author : T.K. Hareendran - Copyright: Electronics For You

Readmore → Simple Cell Phone Controlled Audio Video Mute Switch

Sunday, 5 February 2017

Current Controlled Boost LED Driver and Black Soldermasks

The MAX16834 is a neat little chip (it's not the only one, there are plenty of others out there) that allows high efficiency designs for LED string driving. It provides a platform for a Buck or Boost converter design, as well as brightness adjustment via analog/PWM input pins, as well as a fault output (in case of open/short circuits for example) and also diverse other functionalities that can be quite useful. [ ]

Readmore → Current Controlled Boost LED Driver and Black Soldermasks

Saturday, 7 January 2017

Temperature Controlled Soldering Iron

Description

One reason why commercial soldering stations are expensive is that, in general, they require the use of soldering irons with inbuilt temperature sensors, such as thermocouples. This circuit eliminates the need for a special sensor because it senses the temperature of a soldering iron heating element directly from its resistance. Thus this circuit will, in principle, work with any iron with a resistance which varies predictably and in the right direction with temperature (ie, positive temperature coefficient).

A soldering iron that’s ideally suited for use with this controller is available from Dick Smith Electronics (Cat T-2100). This circuit runs from a 12V battery or a mains-operated DC source. It works as follows: a DC-DC converter (IC1, Q1, D1, Q2, T1, D2, L1, etc) steps up the 12V DC input to about 16V. The higher voltage boosts the power to the iron and reduces warm-up time. This output voltage is applied to a resistance bridge in which the heating element of the iron forms one leg.

Circuit diagram:

Temperature-Controlled Soldering Iron Circuit Diagram

The other components of the bridge include resistors R7-R9 and pots VR2-VR4. When the iron reaches a preset temperature, as set by VR4, the output of IC2a goes high, sending a signal to switching regulator IC1. This forces the output of the converter to a relatively low voltage. A bi-colour LED indicates that the iron has reached the preset temperature by changing from red to green. The iron now begins to cool until it drops below the preset temperature, at which point the output voltage from the DC-DC converter goes high again and the cycle repeats.

A degree of hysteresis built into the circuit makes the LED flicker between red and green while the iron is maintained at its preset temperature. Calibrate the circuit as follows: while the iron is still relatively cold, monitor the input voltage and current and adjust VR1 so that the input power (Volts x Amps) is about 50W. When you have done that, set VR4 to maximum and adjust VR2 so that the LED flickers between red and green when the iron has reached the desired maximum temperature.

Finally, set VR4 to mid-position and adjust VR3 so that the LED flickers when the iron reaches the desired mid-range operating temperature. As an example, you might choose to set the maximum temperature to about 400°C and the mid-range operating temperature to about 350°C. The overall temperature range, in that case, should be approximately 280°C to 400°C. Check that the calibration is correct and repeat the adjustment procedure if necessary. Use a temperature probe, preferably one designed especially for soldering irons, rather than guesswork, when making the adjustment.

Note:

VR4 should have a logarithmic taper to compensate for non-linearity in the temperature-resistance characteristic of the soldering iron.

Author: Herman Nacinovich , Silicon Chip

Source http://www.extremecircuits.net/2010/05/temperature-controlled-soldering-iron.html

Readmore → Temperature Controlled Soldering Iron

Thursday, 5 January 2017

Current Controlled Boost LED Driver and Black Soldermasks

Readmore → Current Controlled Boost LED Driver and Black Soldermasks

Tuesday, 15 November 2016

Electronic Temperature Controlled Relay

This temperature controlled relay circuit is a simple yet highly accurate thermal control circuit which can be used in applications where automatic temperature control is needed. The circuit switches a miniature relay ON or OFF according to the temperature detected by the single chip temperature sensor LM35DZ.

When the LM35DZ detects a temperature higher than the preset level (set by VR1), the relay is actuated. When the temperature falls below the preset temperature, relay is de-energized. The circuit can be powered by any DC 12V supply or battery (100mA min.)

Electronic Temperature-Controlled Relay Schematic

temperature-controlled-relay-circuit-diagram

How it works?
The heart of the circuit is the LM35DZ temperature sensor which is factory-calibrated in the Celsius (or Centigrade) scale with a linear Degree->Volt conversion function. The output voltage (at pin 2) changes linearly with temperature from 0V (0oC) to 1000mV (100oC).

The preset (VR1) & resistor (R3) from a variable voltage divider which sets a reference voltage (Vref) form 0V ~ 1.62V. The op-amp (A2) buffers the reference voltage so as to avoid loading the divider network (VR1 & R3). The comparator (A1) compares the reference voltage Vref (set by VR1) with the output voltage of LM35DZ and decides whether to energize or de-energize the relay (LED1 ON or OFF respectively).

Components list:

IC1 : LM35DZ
IC2 : TL431
IC3 : LM358

LED1 – 3mm or 5mm LED

Q1 – General purpose PNP transistor ( A1015,…) with E-C-B pin-out)
D1, D2 — 1N4148
D3, D4 — 1N400x (x=2,,,,.7)

ZD1 — Zener diode, 13V, 400mW

Preset (trim pot) : 2.2K (Temperature set point)
R1 – 10K
R2 – 4.7M
R3 – 1.2K
R4 – 1K
R5 – 1K
R6 – 33Ω

C1 – 0.1 µF ceramic or mylar cap
C2 – 470 µF or 680 µF electrolytic cap. (16V min)
Miniature relay – DC12V DPDT, Coil = 400 Ω or higher

Readmore → Electronic Temperature Controlled Relay

Thursday, 1 September 2016

Topic Electronic eye controlled security system circuit diagram

Post: Electronic eye controlled security system circuit diagram

Electronic eye controlled security system circuit using ldr, Contents. 0.1 electronic eye controlled security system circuit principle: 1 circuit diagram of electronic eye controlled security system: 1.1 electronic eye.

Electronic eye controlled security system - english, Main aim of this project is to provide security to the malls, banks & homes by using electronic eye (ldr) controlled system. read more circuits here..

One transistor electronic code lock system circuit diagram, Contents. 0.1 one transistor electronic code lock system circuit principle: 1 one transistor electronic code lock system circuit diagram: 1.1 simple transistor code.

Integrated circuit - wikipedia, the free encyclopedia, Terminology. an integrated circuit is defined as: a circuit in which all or some of the circuit elements are inseparably associated and electrically interconnected so.

Television / video electronic circuits, page 1, Television and video electronic circuits, schematics or diagrams, page 1. discovercircuits.com is your portal to free electronic circuits links. copying content to.

Eye blink sensor & accident prevention - spogel.com, To unconscious through eye blink. here one eye blink sensor is fixed in circuit diagram: 2.3.parts of the system: eye blink sensor & accident prevention.

There are eight reasons why you must think Electronic eye controlled security system circuit diagram
Find here about Electronic eye controlled security system circuit diagram
and your search ends here the results of research that many people look for a pdf version too to find Electronic eye controlled security system circuit diagram
here is the content

Pictures Electronic eye controlled security system circuit diagram

ELECTRONIC EYE CONTROLLED SYSTEM (SHADOW DETECTOR ALARM) | Muettech

Photodiode Alarm Circuit IC CA3130 Datasheet

Readmore → Topic Electronic eye controlled security system circuit diagram