I O Experimenter Board PCB Version

If you are tired of connecting the same I/O devices every time you prototype a new project then this board could save you a lot of time. All the necessary pins of the devices on the board are accessible through headers that allows easy connection of the board to a breadboard circuit or other development boards (Arduino, etc) using jumper wires.

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LV8741V PWM Stepping Motor

Using the LV8741V PWM stepping motor driver IC can be designed a very simple and efficiency DC motor driver electronic project . As you can see in the circuit diagram , this electronic project require few external electronic parts . The maximum output current that can be provided by this PWM current-control stepping motor driver IC is up to 1.5 ampere . The reference voltage is set by the voltage applied to the VREF pin and the two inputs ATT1 and ATT2.

LV8741V PWM Stepping Motor Circuit Diagram

When the output current is below the output short-circuit protection current, the output is controlled by the input signal. The setting conditions for the above PWM current-control DC motor driver circuit diagram are as follows : Auto recovery-type output short-circuit protection function (EMM = Low), Output enable function fixed to output ON state (OE = High), Current limit reference voltage setting = 100% (ATT1 = Low, ATT2 = Low) ,Chopping frequency : 37kHz (RCHOP = 43k ).

Voltages required by this LV8741V current-control DC motor driver are from 9.5 to 35 volt for motor power and from 2.7 to 5.5 for logic power supply .

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Headphone Amplifier with IR Communication

This low cost project can be used to reproduce an audio from TV without creating any disturbance from other people. No wire will be used by the circuit between the TV and the headphone because instead of using wires, it utilizes the invisible infrared light for the transmission of audio signals from the TV going to the headphone. The range that can be covered can reach up to 6 meters without using any lens but if required, the range can be made to extend with the use of lenses and reflectors with transmitters and receivers that comprise the IR sensors.

Headphone Amplifier with IR Communication Circuit diagram

Two series connected IR LEDS are being driven by the two-stage transmitter amplifier that uses the IR transmitter. The audio output from TV to the IR transmitter is coupled by using an audio output transformer that is reversely connected. The audio signals are amplified by the transistors BC547 & BD140. These audio signals are received from TV through the low output impedance windings for TV connection of the audio transformer while high impedance for IR transmitter connection.

A 9V source can power the IR transmitter with the LED functioning as power-on indicator.

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Battery Charger Using LTC4078

Using the LTC4078 standalone linear charger circuit you can design a very simple single-cell battery charger circuit for Li-Ion Li-Polymer battery . This LTC4078 battery charger circuit works from both wall adapter and USB inputs. This charger can detect power at the inputs and automatically select the appropriate power source for charging.

Battery Charger Using LTC4078 Circuit diagram

As you can see in the circuit diagram , this Li-Ion Li-Polymer charger requires few external components and you will need to apply just few equations ,to design a full work USB , wall adapter charger .
The charge current can be programmed up to 950mA from wall adapter input . IUSB pin is used for program the charge current for USB power that can be programmed by connecting a resistor to the ground.

The voltage on this pin can be used to measure the battery current delivered from the USB input using the following formula: IBAT = (VIUSB/RIUSB)*1000 . ITERM pin is the termination current threshold program that is set by connecting a resistor to ground. ITERMINATE is set by the following formula:
ITERMINATE =100V/RITERM ; RITERM =100V/ITERMINATE IDC pin is used for program the charge current for wall adapter power that is set by connecting a resistor to ground.The voltage on this pin can be used to measure the battery current delivered from the DC input using the following formula: IBAT = (VIDC/RIDC)*1000 .

The charge current delivered to the battery from the wall adapter or USB supply is programmed using a single resistor from the IDC or IUSB pin to ground and can be calculated using the following equations:
RIDC =1000V/ICHRG-DC , ICHRG-DC = 1000V/RIDC - Wall adapter
RIUSB =1000V/ICHRG-USB , ICHRG-USB =1000V/RIUSB – USB port.

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