"low-power" refers to components and circuits which are designed to have a lower power consumption than their common counterparts. This is most often a requirement because of limited available power, as in battery operated devices.

learn more… | top users | synonyms

8
votes
9answers
1k views

Avoiding DC voltage drop over long distances

I am trying to power my IP camera over a long distance from the power socket (about 10m). The included power adapter, rated for 5V 2A is about 1.5m long. I cut the cable and extended it using a ...
5
votes
3answers
150 views

ATtiny85 power consumption double expected

I'm trying to get an ATTiny85 to run off a battery. I have it clocked from a 16.384 MHz crystal, with the divide-by-8 fuse set. Vcc is 3.3 volts. Figure 22-7 in the datasheet says that at idle ( ...
0
votes
1answer
50 views

Shutdown mode in si4010 microcontroller

I'm working on a project with si4010 microcontroller plus a battery and I want to save power, so I have to enable the shutdown mode. I need to wake up every 1s and do the process and then go back to ...
1
vote
4answers
78 views

Very low-quiescent (<2mA), 5V, simple “speaker” driver

How can I drive a 30ohm speaker from a 5V microprocessor in a simple, very low quiescent-current (<2mA) manner? The "speaker" is actually a coil, not a speaker - and I'm trying to induce a ...
3
votes
4answers
360 views

What are some of the segmented displays with the lowest power consumption?

I have to select a low-power display for a solar-powered digital clock. I have looked into numerous technologies, including e-ink. However, I was still unable to compare between them due to the lack ...
2
votes
1answer
71 views

PIC32 sleep mode with watchdog wakeup failing

I am in the process of trying to get a PIC32MX795F512L to run with lower power consumption. I'm trying to get it to enter sleep mode and then be woken by the watchdog timer. All pretty standard ...
0
votes
0answers
66 views

powering a micro in sleep mode

I've got a setup that will spend 1/3 of its time running a few servos (figure up to 1A @ 5V), 1/3 running sensors / other (<300mA @ 3.3V), and 1/3 of its time sleeping with just the watchdog ...
1
vote
2answers
62 views

Is it safe to not power this USB to I2C chip when USB isn't plugged in?

I am working with someone on a data logger based on an MSP430. Since it operates on battery power, we want the device to use as little power as possible. We are planning to use this chip (FT201X) to ...
2
votes
2answers
190 views

ATmega328P running on CR2032 has issues with timing/sleep code as voltage depreciates over time

I have an ATmega328P running at 16 Mhz on CR2032 with a few sensors and radio for about a week now. It started out at 3+ Volts and is currently measuring at 2.96 Volts. At present, I am not using ...
2
votes
1answer
78 views

calculating total power consumption with LDO vs switching regulator

I'm just getting somewhat familiar with voltage regulators and am trying to make sure I'm understanding a bunch of parameters correctly. Scenario: I have a project that spends 1/3 of its time ...
2
votes
3answers
131 views

What happens when current sourced from a switching regulator goes too low

On the recommendation of an SO-er, I'm looking at using a TPS54295 to power a controller that uses an ATMega 2560. The regulator will be powered by a 3-cell LiPo battery, implying input voltages ...
0
votes
3answers
126 views

Multiple voltages off a single source

I'm building a controller for project that has hobby servos. These typically need ~5V to run. The controller will be an ATmega 2560, running at 3.3V / 8MHz. Looking at the reference design for the ...
0
votes
1answer
124 views

Reducing current consumption in deep sleep mode

This is in relation to the question I asked about deep sleep mode. I'm using PIC18F and it says in the datasheet that in deep sleep it would consume only few nA. But when I configured for deep sleep ...
3
votes
2answers
75 views

RF Wakeup - Battling power consumption

I am currently using two nRF24L01+ (2.4 GHz RF transceivers) together with two AVRs to create a keyless entry system. My problem is battery lifetime when using a CR2032 battery to power the key. The ...
0
votes
5answers
168 views

Best choice for low-power, short-range wireless communication

I'm working on a project which relies on wireless communication, and I'm looking for the best alternative. These are the design requirements: Is easy to interface with Arduino Works over a small ...
2
votes
1answer
79 views

What kind of solar panel is required to keep a mobile alive forever?

I want to build a webcam from an old mobile and I want it to be solar powered. The phone use a 3.7V lithium-ion battery of 1500mAh capacity. The phone last 24h hours on one charge. So if I'm right, ...
-1
votes
2answers
113 views

How long will this low duty 555 LED blinker last on batteries?

I know there are many questions about LED blinkers, but I haven't yet found a clear answer for this. I have a 555 circuit blinking a blue led (or three in parallel). I has a low duty cycle (using a ...
4
votes
3answers
150 views

Using timer to power on/off a high current circuit

I'm working on a Arduino project that takes measurements from the environment and sends them to a remote server over WiFi. The circuit should be battery powered and I've measured that what I have at ...
1
vote
1answer
96 views

Implementing dynamic frequency scaling on PIC32 by changing PLL multiplier/divider?

I read in the PIC32 Reference Manual that one can change the PLL multiplier and divider at run-time, provided that the input frequency is between 4 and 5 MHz and the resulting frequency does not ...
0
votes
1answer
223 views

How to power Raspberry Pi with a Flight Controller

I am making an autonomous quadcopter and I need Raspberry Pi on board to implement image processing. The issue is that I have a 4in1 ESC which comes with only one UBEC to power the flight controller, ...
1
vote
2answers
58 views

How to fit back-up battery into the controller board? [closed]

I'm newbie in the field of PCB making and I have one relevant question. I have a controller on a PCB which has many resistor dividers and passive components. I would like to know, if I want to make ...
0
votes
2answers
51 views

Devices which consume substantial power in modern embedded real-time systems? [closed]

Could anybody cite examples (if any) of devices and peripherals in modern embedded and real-time systems which consume substantial amount of power compared to modern processors. As processors get more ...
0
votes
2answers
78 views

How to interface a SPST switch with minimal current (1µA)?

The usual way to wire up a SPST switch to a MCU is by means of a pull-up resistor. However, this wastes current when the switch is closed. If this switch is used to wake up the MCU from sleep, then ...
1
vote
1answer
165 views

Preventing parasitic powering of FT232RL by ATMega328P

I have a battery powered board with an ATMega328P and some other peripherals such as SD card, RTC, sensors, etc. The design of the board is to be as low power as possible, whilst keeping with the ...
1
vote
0answers
80 views

Can BJTs operate in the nano-ampere range?

Can BJTs can operate predictably with very low currents, in the order of nano-amps or less? I am involved in microelectronics design and have made a voltage reference chip that is MOSFET-only and ...
2
votes
2answers
79 views

low power displays

What kind of displays can I use effectively with a coin cell battery (CR2450)? The backlight or the entire display would be on only when necessary. From previous answers I know that a liquid crystal ...
1
vote
1answer
81 views

Latch power on-off circuit

See the circuit below: I am trying to make a shutdown circuit for a low power application. Basically, I want the system to be able to be turned on by a button push, and then turned off by a ...
0
votes
1answer
81 views

Low power timer circuit for solar tracking

I'm making a solar based device but it needs to be aligned according to sun's position in sky , the whole assembly needs to move around 11 degree/hr. So I was thinking of using a timer circuit (low ...
2
votes
1answer
130 views

how does a cell phone transmitter work?

I came across a question that is really puzzeling me. I did some basic calculation for a cell phone transmitter. I based on 900Mhz band and assumed a 20Km distance to a cell tower. On top of that I ...
0
votes
2answers
105 views

Low voltage (<3V) signalling on USB DP/DN - will it work?

I'm using a microcontroller (specifically, the STM32L1) that integrates a USB device full-speed interface. I want to supply it with just 2V VDD, which is within spec for that micro. But that means USB ...
2
votes
2answers
138 views

Unpowered devices on I2C/SPI bus

I'm trying to develop a board that includes I2C and SPI devices that are unpowered for the majority of the time to save power. I found that for these particular devices (Honeywell HSC pressure ...
2
votes
2answers
152 views

What is the tiniest, low-power, and efficient am transmitter?

Here are my constraints: I need to build an am transmitter, but it has to fit in a 1 inch diameter and ~1 inch height box. Since the box is very small, I plan to use a CR2032 battery, which is also ...
0
votes
1answer
111 views

Solar Charge Battery Low Voltage Disconnecting

I have a 4.2V 120mA max solar panel and 3.7V 1200mAh battery. I'm trying to make a solar power system for my arduino. I search through battery management IC's and generally understand the charge ...
6
votes
1answer
1k views

Replacing incandescent bulbs with LEDs, unexpected behavior

I have an over-the-stove microwave/ hood vent combo with 2 adjustable-brightness lights. The lights appear to be 12V lamps with a G4-style connector, and they burn out all the time... like every 4 or ...
1
vote
2answers
143 views

Voltage regulator help

I need help with what is probably a very simple question that I don't know. When you put 12v at 10 watts and bring it down to 5v with a regulator would the wattage change? And just say the regulator ...
2
votes
1answer
49 views

making sense of HCT ACT cmos “addional supply current”

I'm trying to make a low-current level shifter from low voltage (~2V) CMOS up to 5V CMOS. I had the idea to use TTL-compatible CMOS gates in the HCT or ACT families. But this line in the 74HCT04 ...
0
votes
2answers
148 views

3.7v > 3.3v voltage stepdown with logic-driven on/off control [paused]

(PAUSED): This topic is currently on hold as I source necessary hardware. I need to connect a Wi-Fi/RS232 module to a low-powered monitoring device, and for maximum portability, I'd like to power the ...
1
vote
1answer
114 views

Do any rotary encoders allow zero idle current

Many microcontrollers and logic devices (programmable or otherwise) are capable of drawing very little current when nothing is happening. If a double-throw switch is wired to such a device, then when ...
2
votes
0answers
108 views

First project, powering an IC

I am working on a RGB LED Strip controller to light the inside of my PC. I plan to use a Molex connection 12V DC to power the circuit, the LEDs I am using can run up to 12V, but it should run at about ...
0
votes
0answers
71 views

Relay needed for an input ot 0.15 V

sorry about the question but I'm a beginner here. I have a very low DC voltage of 0.15V and I want to use a relay with in a simple circuit to light a LED. I'm learning in how to build circuits. So ...
0
votes
0answers
227 views

Trying to use INA2128 op-amp (or INA128, a similar model) in Proteus ISIS

I'm trying to simulate an EMG-signal amplifier that I got the schematic for from one of my seniors at my university. The signal strength varies from 3mV to 10mV, and the amplifier takes it up to 5V. ...
3
votes
5answers
376 views

Are opamps as a voltage regulator effcient?

If I setup an opamp in a non-inverting configuration as follows: Vrail+ is 7.5V, Vrail- is GND (0 V) Vin is 2.5V, Vout = 3.3V (in other words, the gain, aka, 1+R2/R1 is 1.32 [V/V]) Iout = 100mA ...
1
vote
2answers
221 views

How can I create a theatrical spark ejector?

I'm involved with an amateur theatre company (I do lighting, audio etc...) and would like to simulate a switch short-circuiting. I have also done a bit of magic in my time and have used "spark ...
-1
votes
1answer
51 views

USB Compliant Power/Charging Circuit [closed]

I am designing a device that can charge a USB device, such as a cell phone. I have a 5v DC output source from my device. I know I can just tie D+ and D- together, and connect the 5v to the power pins, ...
1
vote
1answer
100 views

Looking for a 3.3V IR sensor [closed]

I am currently using a SHARP GP2YOA21 infrared distance measuring sensor which is 5.0V. I am looking for an alternative IR sensor that would work with 3.3V. Our application involves wireless sensor ...
3
votes
5answers
182 views

How much current is used with a μC GPIO input and pullup resistor?

I'm trying to understand power budgets a bit better and I have a question regarding pullups. I have a input to a microcontroller that needs to be logic high at all times. The micro goes to sleep now ...
1
vote
1answer
63 views

power leaking from device via USB

In my car I have power converter for the cigarette lighter. This power converter has some 3 USB ports and 2 cigarette lighter ports. I have devices plugged into the cigarette lighter ports. One of ...
0
votes
1answer
417 views

Backup power for adsl modem

I want to create a circuitry for switching to backup power (small battery) in case of mains power failure for my ADSL modem (to avoid the internet going down in such scenario). This is a basic ...
3
votes
2answers
117 views

Checking whether two voltages are similar

I am pretty new to electronics so this may seem like a basic question, but how could I check whether two voltages are similar? For example, say I want to check whether | V1 - V2 | < 1.5V and output ...
3
votes
2answers
119 views

Designing a mixed signal circuit for the first time

I am designing my first mixed signal circuit. I will then have a analog and digital ground plane and my question is: To be able to have separate grounds (analog and digital) on a battery powered ...