3 Volts Car Adapter Using LT1074CT

This circuit is based on a standard LT1074CT switching regulator IC. For sure, Application Note AN35 published by Linear Technology describes the design far more elegantly than the author could in this short article. Interested readers are therefore strongly advised to get a copy of AN35. The schematic shows the LT1074CT used as a positive step-down or ‘buck’ converter. The ‘switcher’ is used to convert a +12-volt car battery voltage down to +3 volts for use with the personal hi-fi’s and hand-held games for the author’s two boisterous children on long car journeys. Note at under ten years of age, children will rarely be hi-fi aficionado’s and are generally not concerned with any noise generated by the ‘switcher ‘circuit.

The circuit is connected to the car +12-V system via the cigarette lighter socket — is advisable to use a fused version of the cigarette lighter plug. The +12-V arrives on the board via screw- terminal block J2. Diode D2 provides a reverse voltage protection, while C3 decouples the input to the switcher IC. The LT1074CT briskly switches the supply voltage on and off in response to the signal applied to its F/B input, to the extent that the average output voltage is at the required level. The values of potential divider resistors R1-R3 have been chosen to attenuate the output voltage so that there is 2.5 V at the F/B pin.

The difference between the attenuated output voltage and the internal 2.5-V reference is used to control the modulation effect of the switcher. Components R2 and C2 provide frequency stabilization for the feedback loop. Inductor L1 along with the LT1074CT form the main switching components, while C1 provides decoupling for the output load. The 3-V output voltage is taken from screw terminal J1. With this circuit built, boxed up and installed in your car, you can look forward to possibly your first ‘quiet’ long car journey.

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Basic devices in the car audio system

Entertainment in the form of music, news or even movies, generated from a series of audio devices found in a car. The series device known as a car audio system.

What tool or device contained in car audio system?

• Car Head Unit - Head unit is the core of a car audio system, part of the car audio system that plays sound. The continued development of technology makes the head unit is no longer only serve as a radio receiver FM / AM CD player and a player, some have additional functions to be able to play MP3s. There is also a car head unit that has the ability to play DVDs complete with monitors and can be connected with IPOD.
• Power Amplifier - The function of the power amplifier is to amplify the signal coming out of the head unit. In the world of various types of car audio power amplifiers are divided into several classes, such as class A, B, AB, and D. Each class power amplifier has the advantage that its usefulness can be tailored to our needs in building a car audio system. In addition to class division, the division of power amplifiers can also be seen from the number of channels (channels) and the amount of power generated by the power amplifier.
• Speaker - A device that functions convert electronic signals into audible sound. The speakers were divided into several parts / components, namely, subwoofers, woofers, mid-range, and tweeter. In order for speakers to work properly, required a series of electronic components that serves as a filter (cross over).
• Processor - With advances in technology processors play a significant role in a car system. Inside there is a processor features like time correction, cross-over-active, etc. equalizer. With the functions it will be very easy at the time of tuning car audioaudio system.

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Mobile Car Stereo Player

Using a mobile phone while driving is dangerous. It is also against the law. However, you can use your mobile phone as a powerful music player with the help of a stereo power amplifier. This does away with the need of a sophisticated in-dash car music system. Most mobile phones have a music player that offers a number of features including preset/manual sound equalisers. They have standard 3.5mm stereo sockets that allow music to be played through standard stereo headphones/sound amplifiers. Nokia 2700 classic is an example.

Mobile Car Stereo Player Circuit Diagram

A car audio amplifier with 3.5mm socket can be designed and simply connected to the mobile phone output via a shielded cable with suitable connectors/jacks (readymade 3.5mm male-to-male connector cable is a good alternative). Fig. 1 shows the circuit of car stereo player. It is built around popular single-chip audio power amplifier TDA1554Q (IC1). The TDA1554Q is an integrated class-B power amplifier in a 17-lead single-in-line (SIL) plastic power package.

IC TDA1554Q contains four 11W identical amplifiers with differential input stages (two inverting and two non-inverting) and can be used for single-ended or bridge applications. The gain of each amplifier is fixed at 20 dB. Here it is configured as two 22W stereo bridge amplifiers. The amplifier is powered from the 12V car battery through RCA socket J2. Diode D1 protects against wrong-polarity connection. LED1 indicates the power status.

Stereo Jack :

(a) 3.5mm stereo socket and (b) 3.5mm Stereo Jack

Connect stereo sound signal from the 3.5mm headset socket of the mobile phone to audio input socket J1. When you play the music from your mobile, IC1 amplifies the input. The output of IC1 is fed to speakers LS1 and LS2 fitted at a suitable place in your car. Electrolytic capacitor C5 connected between pin 4 of IC1 and GND improves the supply-voltage ripple rejection. Components R2 and C4 connected at mute/standby pin (pin 14) of IC1 eliminate the switch on/off plop. The circuit is quite compact. A good-quality heat-sink assembly is crucial for IC1. Fig. 2 shows the stereo socket and stereo jack.

Proposed enclosure

Assemble the circuit on a general-purpose PCB and enclose in a suitable cabinet. Small dimensions of the power amplifier make it suitable for being enclosed in a plastic (ABS) case with vent holes. Signal input socket, speaker output terminals, on/off switch, indicator, fuse holder and power supply socket are best located on the front panel of the enclosure as shown in Fig. 3.

Source : http://www.ecircuitslab.com/2012/04/mobile-car-stereo-player.html

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1995 Lincoln Town Car v 8 Wiring Diagram

1995 Lincoln Town Car v-8  Wiring Diagram

(click for full size image)

The Part of 1995 Lincoln Town Car v-8  Wiring Diagram : glove box lamp switch, glove box, left vanity mirror lamp, switch, grounds, solid state, garage door, engine compartment lamp, hodd, trunk lid lamp switch, trunk lid, front dome switch, lamp, rear dome switch, lamp.

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Car Stereo Amplifier using TDA 2040

A car stereo amplifier using TDA2040
circuit shown here. TDA2040 is a monolithic integrated audio amplifier
operating in Class AB mode. The IC has built in short circuit
protection circuits and thermal very close and more about it can be
operated from a single source. The amplifier can deliver 12 watts into a
8 ohm speaker.

In the circuit of the IC is connected to
operate from the 12V line cars. Capacitor C7 is a DC-decoupling
capacitor and R4 provides. Network consisting of resistor R5 and
capacitor C5 provides high frequency stability and avoids any
possibility of oscillation. C6 capacitor couples the output circuits to
the speaker. C2 and C1 are the filters of the power supply.

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Best Automatic Car Alarm

Even the best car alarm is useless if you forget to set it upon leaving your car, whence this circuit. The relay has a make and a break contact: the  former is necessary to delay the switching in of the  alarm after you have got out of your car, and the  latter serves to switch on the car alarm proper. Immediately on re-entering your car, you must press the hidden switch, Si. This causes silicon-controlled rectifier Thi to conduct so that the relay is energized. At the same time, the green LED lights to indicate that the alarm is switched off. 

 Best Automatic Car Alarm Circuit Diagram

As soon as the ignition is switched off, T, is off, T2  is on, and the buzzer sounds. At the same time,  monostable IC1 is triggered, which causes T3 to  conduct and the red LED to light. The silicon- controlled rectifier is then off, and D4 is reverse  biased, but the relay remains energized via its make  contact for a short time, preset by Pi As soon as this  time has lapsed, the relay returns to its quiescent  state, and the alarm is set via the break contact. The  delay time can be set to a maximum of about 1 minute.

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