0
If a phone needs a 7v 900ma charger can you use a 9v 400ma if the voltage and polarity are the same?
Wiki User
∙ 8y ago
The volts MUST match exactly, the polarity MUST match exactly, and the milliamps MUST be the same or more. The unit will use what it needs, even if to much is being offered. On the other hand, too few milliamps will BURN THE UNIT OUT!
So on top of loosing your equipment, you could loose your life also ... since it is a major fire hazard!
Clearly the voltage is not the same. The phone needs 7V, the charger is at 9V. Mismatching voltage will not work.
Using a power supply with a maximum current rated below what is required will result in 1) the supply voltage dropping, and 2) the device generating additional heat. Such low power requirements do not present a serious hazard, fire or otherwise. However, the higher voltage will likely seriously damage the phone. Had the supply you chose been rated at 7V 400mA, the phone would likely still charge, albeit much more slowly.
Wiki User
∙ 8y ago
Add your answer:
Earn +20 pts
What is difference between 550 mah and 900 mah in mobile phone charger?
The charger with the 900ma output will charge the battery faster than the charger with a 500ma output. The phone with the 900mah battery will last longer between charges than that of the 500mah battery.
What is the power rating in a Nintendo 3ds?
The power rating is on the bottom of the 3ds, the power rating is 4.6V 4.1W, the power suply input is 4.6V 900mA. the DSI charger will work on a 3DS.
How many amps goes into 900ma?
.9A
Is it possible to over use your power supply in the usb outlet?
Yes. A standard USB Plug can provide <at usb2.0> 500mA of power. Some devices if poorly made or malfunctioning could draw too much of that power over a chain of devices and cause the port to shut down. It will not, in most cases, damage the power. The port will detect an overage in power demand and shut itself down. Usb 3.0 allows for at most 900mA of power.
How many mAh in AA battery?
Zinc-carbon AA =400-900 mah Alkaline AA = 1700-3000 mah :: I believe the above answer to be misleading/misguiding, the question is "How much mA does a single AA battery have?" not how many mAh. in mA a single AA batter will have about 3.6mA to 4.0mA it is important to distinguish mA from mAh, if one were to connect a device that required 4.0mA to a power source of 400-900mA this would likely destroy the device. mAh deals more with how long the battery life lasts.
The usb and firewire bus standart and their possible impact on computer of the future?
USB AND FIRE WIRE BUS STANDARDS AND THEIR POSSIBLE IMPACT ON COMPUTERS OF FUTUREUNIVERSAL SERIAL BUS (USB):-A USB flash drive is a data storage device that consists of flash memory with an integrated Universal Serial Bus (USB) interface.· It is hot swappable.· USB version 1.1 provides maximum speeds of up to 1.5 MB/s while the version 2.0 is about 40 times faster.· Most weigh less than 30 g.· Drives of 256 gigabytes (GB) are also available, and storage capacities as large as 2 terabytesInternals of a typical USB flash drive1USB Standard-A plug2USB mass storage controller device3Test points4Flash memory chip5Crystal oscillator6LED7Write-protect switch (Optional)8Space for second flash memory chipUSB STANDARDS:-USB (1.x and 2.0):-USB 1.x provides low speed (up to 1.5 M Bit/s) at distances of 3m, and high speed (12 M Bit/s) at distances of 5m.Version 2.0 supports speeds to 480 M Bit/s at distances of up to 5m.In all cases a maximum of 5 hubs may be supported.USB (1.x and 2.0) provide a base current of 100MA and a maximum current of base X 5 = 500MA for powering of peripherals or battery charging applications.USB 3.0:-USB 3.0 provides speeds up to 5.0 G Bit/s - termed Super Speed in the specifications. USB 3.0 uses new Standard and Micro A and B plugs and receptacles using 9 pins to obtain the full Super Speed performance (5.0 G Bit/s). USB 3.0 increases the base current from 100MA (USB 2.0) to 150MA. The maximum load is 6 x base to 900MA (up from USB 2.0 x 5 = 500MA).USB 0.7 :-· Released in 1994· Voltage - Input2.7 V ~ 5.5 V· Current Limit= 700mA· Operating Temperature= - 40°C ~ 85°COTHER STANDARDS:-· USB 0.8: Released in December 1994.· USB 0.9: Released in April 1995.· USB 0.99: Released in August 1995.FIREWIRE BUS:-FireWire is High Performance Serial Bus, for connecting devices to your personal computer. FireWire provides a single plug-and-socket connection on which up to 63 devices can be attached with data transfer speeds up to 400 Mbps.It is Hot-plug and plug and play capability without disrupting your computer.FIREWIRE STANDARDS:-FIREWIRE 400 (IEEE 1394):-High interface transfer rate: up to 50MB/s.Flexibility: use your IEEE 1394 peripheral on both Mac or Windows platforms.Ease of use: hot-pluggable FireWire technology.Small cables: space-saving thin serial cables.Connect up to 63 devices.Self-powered: directly powered by the bus.The IEEE 1394 interface is specifically aimed at multimedia peripherals such as digital video camcorders, CD-RW drives, DVD drives and hard drivesFIREWIRE 400 (IEEE 1394a):-Brings high-speed connectivity to your desktop computer, quickly and easilyIt added support for asynchronous streaming, quicker bus reconfiguration, packet concatenation, and a power-saving suspend mode.Great for use with multimedia peripheralsFirewire 400 (IEEE 1394a) provides 100, 200 and 400 Mbits/sec transfer at a distance of 4.5 meters between devices.FireWire 800 (IEEE 1394b)· FireWire 800 (IEEE 1394b) increased transfer rate to 800 Mbits/sec and cable distance to 100 meters in 2003. · It also expanded cable options to glass and plastic fiber and Cat 5 Ethernet.· Also included in IEEE 1394b, FireWire 1600 and FireWire 3200 increase transfer rates to 1.6 and 3.2 Gbits/sec respectively.· FireWire 800's connector, referred to as a beta connector, is different from FireWire 400's alpha connectors, making legacy cables incompatible.FireWire S800T (IEEE 1394c):-· High Performance Serial Bus Amendment to enhance the physical layer for higher data rates over CAT5 or better rated UTP cable Scope. · This is a full-use standard whose scope is to amend the IEEE 1394 base standard (IEEE Std 1394-1995 as amended by IEEE Std 1394a-2000 and IEEE Std 1394b-2002) to specify alternate physical layer(s) that provide greater than S100 data rate over CAT5 or better cable.· This physical layer is capable of negotiating with a peer device to select the appropriate next higher protocol layer.Future enhancements (including P1394d)A project named IEEE P1394d was formed by the IEEE on March 9, 2009 to add single mode fiber as an additional transport medium to FireWire. P1394d - IEEE Standard for a High-Performance Serial Bus - Amendment: IEEE 1394 Single-mode Fiber Fiber Physical Medium (PMD) SpecificationOther future iterations of FireWire are expected to increase speed to 6.4 Gbit/s and additional connectors such as the small multimedia interface. IMPACT of USB and FIREWIRE on future Computers:-USB and Firewire represent the newer generations of external serial interfaces being adopted to reduce PC and connection costs and to improve performance.BY :- AWAD ZAFAR
