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Looking for an efficient USB charger that can operate from a 12V car battery? This unit functions at up to 89% efficiency and can charge USB devices at currents up to 525mA. Best of all, it won’t flatten the battery if it's left permanently connected, as long as you remember to unplug the USB device. There are lots of USB chargers on the market but this device has two stand-out features: high efficiency and low standby current. In fact, its standby current is just 160µA, a figure that’s well below the self-discharge current of most lead-acid batteries. This means that you can leave the device permanently connected and it will not cause that battery to go flat (or at least, not much faster than it would of its own accord). Picture of the project: Why is this useful? Well, in September 2009’s “Ask SILICON CHIP” section, D. E. of Ainslie, ACT asked if it was possible to connect a 12V-to-5V USB charger directly to the battery on a motorbike. His reason for wanting to do this is that ...

It's a great convenience that most modern cars come with a built in alarm, however it is nothing but noise pollution that the horn sounds when the alarm is armed. Disconnecting the alarm system from the horn relay will eliminate this, but prevent the horn from sounding in the even of an actual alarm. This circuit serves to silence the arming beep yet maintain the alarm by introducing a small delay into the signal. It sits between the alarm and horn relay. The alarm must provide a constant horn signal for at least 3 seconds before the horn relay is activated. That way the quick "beep" will never activate the horn relay, while the constant alarm signal will.   Sourced by Part Total Qty. Description Substitutions C1 1 0.01uF Ceramic Disc Capacitor C2 1 100uF 35V Electrolytic Capacitor R1 1 1K 1/4W Resistor R2 1 10K 1/4W Resistor R3 1 15K 1/4W Resistor R4 1 470 Ohm 1/4W Resistor D1, D3, D4 3 1N4004 Rectifier Diode D2 1 Red LED U1 1 555 Timer IC K1 1 SPST 12V Automotive Relay ...

The car cigarette lighter socket does not only light cigarettes, but can be utilized as an electrical channel for powering tools to work on the car such as laptops and other electronic devices. The following circuit diagram shows a way of powering a two-way mobile radio using the LM317 T voltage regulator . The LM317 T is an adjustable 3-terminal positive voltage regulator that efficiently provides a load current of 1.5 Amps over an output range of 1.2 V and 37 V. With reference to the circuit, it can accept 14 volts without any hassle and the voltage can be controlled easily with the use of a potentiometer, a 3-terminal resister with sliding contact. The whole circuit will contain the following components:  Printed Circuit Board (PCB) Resistor 1 (R1): 270 ohms Resistor 2 (R2): 2K carbon potentiometer Capacitor 1 (C1): 100nF Capacitor 2 (C2): 1uF tantalum LM317T Voltage Regulator Heat Sink DC Power Jacks Green LED: Power Red LED: Over Voltage Zener Diode: over voltage LED switch Th...

This circuit is used to monitor the battery voltage to display a dual-colored LED status of the battery to. If the LED “green”battery voltage exceeds 11.9 volts. If the yellow LED , battery voltage 11.9 to 11.5 volts. If the LED is “red” If the battery voltage below 11.5 volts. You can of course change the trigger points by the trimmer resistors and / or changing the value of the resistors in the divider.  .  Simple Car Battery Voltage Monitor Circuit Diagram . A dual op amp is used as a comparator. The green LED on the board, until the voltage exceeds 11.5 volts. The red LED illuminates when the voltage falls below 11.9 volts to the circuit. Therefore, in the 11.9 to 11.5 volts, both LEDs are on, producing a slightly yellow color. When the voltage falls below 11.5 V, the green LED , and now only the red LED flashes to indicate low voltage. Parts List R1=1K2 R2-3-4=680R R5=15K R6=10K R7-8-9-10=1K IC1=LM324 D1=5V6 /0.5W Zener D2-3-4-5=LED RV1=10K trimmer  Is recommend...

IC TA8210AH By using this you can apply a series of audio power amplifier is the car audio system. In general, all the speakers in the car using a subwoofer speaker, and woofer. Because the car is not big room so the sound is being required is not too high. Audio amplifier circuit can work at a minimum voltage 12-volt DC, if supplied under voltage 12-volt amplifier work will be less than the maximum. This amplifier output power up to 200W or 2 x 100W stereo with 8 ohm impedance. Part List : Resistor R1 =1K R2 =50K trim R3 =1K R4 =50K trim R5 =680R R6 =680R R7 =150K R8 =2R2 R9 =2R2 R10=2R2 R11=2R2 Capacitor C1 =1uF C2 =1uF C3 =47uF C4 =47uF C5 =100n/400V C6 =220uF C7 =220uF C8 =100n/400V C9 =100n/400V C10=100n/400V Intregated Circuit IC1=TA8210AH Connector X2-3=in R X2-2=gnd X2-1=in L X1-1,X1-2=Out R X1-3,X1-4=Out L

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.  Circuit diagram : 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 amp...

This is a Simple Car Battery Monitor Circuit Diagram. A close call on the road can really focus your mind on the importance of having a battery monitor in a car. I had been enjoying a pleasant week of travelling around the countryside at a leisurely pace and taking in the beautiful scenery each day. It wasn't until the final day, with the big rush to return home, that I had to drive at night.My home is deep in the country and on the road I was travelling the closest petrol station may be 80km away. I was travelling through an area that is full of open-cut coal mines and large heavily loaded semi-trailers constantly pound the roads, travelling at quite high speeds. It was around 8pm at night and everything was very dark no street lights or house lights anywhere. Just as I was going up a hill, the lights began to dim and the engine coughed. A large semi-trailer loomed in the rear-vision mirror as I pushed the clutch in and tried to restart. My speed was falling rapidly and my lights ...

This circuit using IC LA4445 , this is stereo amplifier with power output 2 X 18 Watt, with this circuit you can use to car amplifier or to other elctronics device. Speaker use woofer with impedance 4 Ohm with power up to 20 Watt. Minimum voltagte require 10 Volt and maximum voltage 18 volt. see schematic below :    If you can't operate the circuit , please check IC , and then voltage in. If voltage is good check the component are. If components are working . Please check speakers.