Today, almost all computers contain logic blocks for implementing a USB port. A USB port, in practice, is capable of delivering more than 100 mA of continuous current at 5V to the peripherals that are connected to the bus. So a USB port can be used, without any trouble, for powering 5V DC operated tiny electronic gadgets.
Nowadays, many handheld devices (for instance, portable reading lamps) utilise this facility of the USB port to recharge their built-in battery pack with the help of an internal circuitry. Usually 5V DC, 100mA current is required to satisfy the input power demand.
To prepare USB Power Socket we require
cigar lighter socket is fed to an adjustable, three-pin regulator LM317L (IC1) Capacitor C1 buffers any disorder in the input supply. Resistors R1 and R2 regulate the output of IC1 to steady 5V, which is available at the ‘A’ type female USB socket. Red LED1 indicates the output status and zener diode ZD1 acts as a protector against high voltage. Assemble the circuit on a general- purpose PCB and enclose in a slim plastic cabinet along with the indicator and USB
socket. While wiring the USB outlet, ensure correct polarity of the supply.
For interconnection between the cigar plug pin and the device, use a long coil cord as shown in Fig. 2. Pin configuration of LM317L is shown in Fig. 3.
Nowadays, many handheld devices (for instance, portable reading lamps) utilise this facility of the USB port to recharge their built-in battery pack with the help of an internal circuitry. Usually 5V DC, 100mA current is required to satisfy the input power demand.
To prepare USB Power Socket we require
- Cigar plug
- Diode
- Resistor & capacitor
- Zener diode
- LED
- Usb type A socket
- IC LM317L
cigar lighter socket is fed to an adjustable, three-pin regulator LM317L (IC1) Capacitor C1 buffers any disorder in the input supply. Resistors R1 and R2 regulate the output of IC1 to steady 5V, which is available at the ‘A’ type female USB socket. Red LED1 indicates the output status and zener diode ZD1 acts as a protector against high voltage. Assemble the circuit on a general- purpose PCB and enclose in a slim plastic cabinet along with the indicator and USBsocket. While wiring the USB outlet, ensure correct polarity of the supply.
For interconnection between the cigar plug pin and the device, use a long coil cord as shown in Fig. 2. Pin configuration of LM317L is shown in Fig. 3.
my project converts 12 to 5 volt but current is just 25mA plz help us
ReplyDeleteIf you are trying to increase voltage then current will decrease . Because current is inversely proportional to voltage.
ReplyDeleteJust use a high input and put an intermediate step down transformer . This is simplest of alll .
remember in this current will "high"
try OPAMP IC 741 or 734
ReplyDelete