"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.

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58 views

Turning-off Watchdog Timer

Under severe power constraints I'm considering disabling the watchdog.The MCU is to work as a stepper motor controller in a watch and drive a simple bar display too. What can the consequences be? (...
2
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3answers
74 views

What's the best way to measure sound at very lower power?

I want to implement a sound meter on a very low power wireless system but I've not had to deal with electret microphones before. The system right now draws around 5uA when in sleep mode, and wakes up ...
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0answers
24 views

Measuring low current on solenoid valve

EDITED - I've made a mistake: P = Ri^2, sorry So, i've been looking for an answer since the beginning of the year. I've digged alot here, talked to professors, but I still have some doubts about this....
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0answers
39 views

Can I detect a weight change without turning on the amplifier?

I noticed that several bathroom bodyweight scales use batteries. I want to make a scale too, so I wired up a circuit with two op-amps that reads the ~10mV readings from the weigh scales. The problem I ...
2
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2answers
84 views

Low power, cost effective way to measure CO2 (or equivalent CO2)?

I'm trying to develop a system that will monitor long term CO2 levels indoors and will run on a battery. A lot of the conventional CO2 sensors are really power hungry and expensive. However, I came ...
2
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3answers
210 views

Improve Rise Time on 1Hz Signal

I am using a MCP79410 real time clock to generate a 1Hz square wave signal (50% duty cycle) for a low power display (Sharp Memory LCD). Without this signal charge builds up and the pixels show burn-in....
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1answer
78 views

Elegant non-mechanical way to switch on battery-powered device the first time

For a primary-battery powered device, that will be stored for a period of time before first use, what is the most elegant non-mechanical* way to switch it on for the first time, after which it will ...
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2answers
41 views

Sizing of and Type of Power-loss / Brown-Out Protection Capacitor

I found a few resources and this question here: power-loss protection I'm using an MCP16301 step down regulator to turn 12v to 3.3v I'm having trouble determining I in this equation: C=I×t/ΔV with ...
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1answer
63 views

how switch between two voltages

I have a project and I need use ISP to send codes to ATMEGA328P, the problem is that my ISP programmer works with 5V and my system works with 3.3V. I know ATMEGA328P supports 5V but other components ...
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0answers
58 views

Lowest energy wireless protocol for specific wireless sensor node

There are so many options for low-power wireless communication these days. BLE is everywhere, and many other manufacturers try to push their protocols as well. LoRa, Dust, Zigbee, Thread, Sigfox, etc.,...
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3answers
164 views

Why filter through hardware?

I am trying to measure a signal with a voltage amplitude between 10-100 microvolts and a frequency between 7-30Hz. The guide I am following suggests filtering out 60Hz noise using a notch filter, as ...
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2answers
158 views

Low power battery backup

I am currently working on a low power battery backed data logger. An Intersil ICL7673 backup switch is used to switch between the battery and external power. Because the circuit draws more than 30mA I ...
2
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1answer
42 views

Efficient low current buck controller topology

In SMPS there are two sources of loss: parasitics, and the controller. Usually, the load consumes more power than the controller, and the parasitic losses dominate. I have the opposite situation. I ...
0
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2answers
65 views

Universal 3.3V & 5V power source for small device

I'm working on a hobby project which combines two modules that require 3.3V @ 130mA and 5V @ 100mA power sources. I want to make my device work at wide range of power sources - from single 3.7V ...
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3answers
151 views

Replace AAA battery with a smaller battery?

I know it is possible to replace a AAA battery with a power source, and that it is possible to use AAA batteries as AA batteries (these are what I find when I google this question). My problem is ...
3
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1answer
57 views

Sensor supplied by MCU - sink or source what is most energy efficient?

I'm building a tiny system for fridge door monitoring. AVR (Attiny13A) is used which is connected to a linear hall sensor OH49E, the complete system is battery powered and I'm trying to minimize power ...
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2answers
37 views

Considerations for switch mode power supply with microcontroller and sensors [closed]

I'm fairly new to this forum and the entire field of electrical engineering. I have a microcontroller (Atmega328P) project that includes a current sensor and several radios (900Mhz-2.4ghz). It is ...
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3answers
1k views

Why does voltage not appear in the battery life calculation?

I have a PCB with a few radio modules on it. In its various states it currently uses anywhere between 100 µA and 100 mA. I can calculate how much time it spends in each of its states over a given year....
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0answers
65 views

What is more power efficient: GPRS or SMS for a GSM sim Arduino application?

I have a GSM shield for my Arduino and am wondering the most power efficient way to receive and send data from and to the cloud. The specific project I am looking to accomplish is starting my car ...
0
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1answer
47 views

operand isolation in RTL

I'm trying to build some low power circuits at the RTL level. How would I go about coding operand isolation so that the synthesis tool (ASIC/FPGA) recognizes it. Assuming the spec requires the output ...
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2answers
95 views

Low voltage drop transistor/mosfet switch - 3.3V 200mA

I need to make a switch. However p-n junction drop seems to be a problem for my use. Hence I am unable to use something like this: In this case, my load won't be getting exact 3.3V across it. ...
0
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1answer
158 views

Arduino and GSM Module running on Li-primary batteries for years

For one of our projects we need to run an Arduino board + GSM module (SIM800C for example) for many years on batteries without recharging. The Arduino should be in power down mode for 99,99% of the ...
1
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1answer
39 views

Solar cell charging and battery chemistry for low power 2.4-3V supply?

I've recently been looking into the possibility of using an amorphous silicon solar cell (like they have in calculators) to supplement my very low power BLE system's current consumption to extend the ...
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0answers
20 views

Building a battery powered flood sensor

I'm trying to design a device to trigger an email when water is detected on a sensor (i.e. a flood sensor for a laundry or similar). For the sensor, I'm considering a couple of electrodes/contacts ...
0
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2answers
65 views

Voltage reference for an OCXO

I have a no-name OCXO with pins marked by seller (VCC, GND, RF OUT, Vadj). I have checked its output frequency against rubidium oscillator using the following method: I connected them both to ...
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0answers
33 views

Dual power supply for the LMV324M

This smartplug reference from TI makes use of a LMV324M for the metrology bit, which is the low power version of the popular LM324. Its being powered from a +/-3.3V supply in the design however the ...
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0answers
102 views

Finding a diode with a low vDrop at low currents

simulate this circuit – Schematic created using CircuitLab So, I'm designing a circuit which has to work with current flowing in both directions through a resistor. I need to measure the ...
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2answers
76 views

Rotary Encoder for Android GPIO

I'm not too sure if this is the place to ask but I'm not sure where else this question belongs. I'm trying to hook up a rotary encoder to an Android dev board's GPIO pins, although I'm having trouble ...
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0answers
50 views

Electronic circuit to power on module in intervals

I have a WeMos D1 R2 ESP8266 based board thats compatible/running Arduino libraries that consumes approx 1.7mA on it's deepsleep. A 9V battery of 600mAh wil last 14 days only using the power of ...
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1answer
21 views

lipo pack to 16vac inverter design

Im looking to drive a 16 vac solenoid from a battery pack. Specifically I want an electric door catch to function when mains are down. I want to do this with out with out using a commercial UPS. Im ...
0
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1answer
16 views

Lower Power Inductive Heating Circuit Design Questions

I'm trying to design a very low power (<=10W) inductive heating circuit that will heat the work material to 40-50degC. I've seen plenty of Royer Oscillator circuits online (see here: http://www....
0
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1answer
74 views

Power supply safety standards

I want to build radio/alarm clock that power itself from the wall. I live in Canada. What safety standards should I follow? And is it free to acquire the datasheet of these safety standards or does it ...
0
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2answers
78 views

LDO regulator below minimum input voltage

I'm designing a circuit that will run from 3V battery. The battery can get as low as 2V and I want to use it as much as I can. I'm using a PIC24 that operates with the integrated regulator for ...
0
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1answer
54 views

Battery Bank - How to achieve full amp-hour ratings with simultaneous series & parallel connections?

I have four 12V batteries (all with the same watt-hour rating), and I would like to achieve dual voltages by interconnecting them, while achieving the following: 48V at the full amp-hour rating of ...
3
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3answers
116 views

How to efficiently power wireless sensor node from a 9V battery?

Context I have recently set out to add some wireless features to my entry-level smoke detector. Problem In order to achieve that, I will be adding a custom pcb embedding an ATmega328P and a ...
0
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4answers
97 views

Implement ac-dc converter for low frequency and very low voltage without external powering?

Iam using a basic cascade voltage multiplier to boost and rectify the 0.3v ac signal. The circuit rectifies but the boost is very less. So I thought of using LTC3105 after this stage to get a ...
2
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2answers
66 views

Low power device in sealed unit — design help

Main question: can I build an arduino-based sensor that'll use such low power that something like inductive charging will suffice to power it? Details: I've got a "holding tank" on my boat ... a 3-...
0
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1answer
50 views

Does it use less power to process and compress data on a chip, or to transmit it to a station?

Let's say I had a grid of force resistors laid out in a pad. Every 5 minutes I'd apply power to the pad and read the resistance of every force resister. The pad itself would be powered by a battery, ...
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0answers
34 views

Is Energia buggy when it comes to using Serial.print() near sleepSeconds() call?

So, I've been experimenting with sleep, sleepSeconds, suspend() and wakeup. These are AWESOME by the way... Here's what I've found. suspend() puts the controller into LPM4 which makes it ONLY come ...
1
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1answer
74 views

Measuring quiescent current of a voltage regulator

I purchased 10PCS Socket Adapter plate Board For NRF24L01+ Wireless Transceive​ module and would like to know how much current/power it will draw as I want to run a project on batteries. A close-up ...
0
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1answer
53 views

Lighting LEDs from high current source [duplicate]

I have an circuit with six high torque servos connected parallel to power brick that provides 5V @5Amps. Everything is running fine. But I wanted to add few LEDs to circuit but I dont know how do I do ...
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votes
1answer
61 views

What's the most efficient way to detect a break in a circuit [closed]

I'm building a sensor that detects when a refridgerator door is left open. my goal is to use 2 contacts that close the circuit when the door is closed. So, when the door is opened, the contacts open ...
1
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1answer
74 views

How do you use low-power mode on an MSP430G2553 using an Energia sketch?

I am using an energia sketch to program my MSP430G2553 controller. I need to know how to use low-power mode. Do I leave the loop section of the sketch empty and set up an interrupt in the setup ...
1
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2answers
110 views

Efficient toggle switch

Is there a way to circuit a power efficient toggle switch controlled by a SINGLE button so that absolutely no current from the power source is drawn at it's OFF ...
0
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2answers
54 views

lowest loss for switch

Are there any other options for an extremely low loss switching circuit with extremely low switching frequency (about 4 times per day) and voltages from 0-3V with currents <2mA. Current ideas ...
0
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2answers
85 views

How to calculate voltage and current of a circuit with input / output MCU pins

I would like to know the method to calculate both voltage and current in a circuit that use MCU input / output pins In this example, how can we find the V / A of all resistances and Capacitors.. ...
0
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1answer
41 views

How to compute the maximum power I can get from an optical fiber?

I'm thinking of a project which requires powering a device with an optical fiber, but I don't know how to compute the maximum amount of power it can supply at the end. These are the parameters I know:...
0
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1answer
52 views

Low RPM, Low Power, Low Torque Motor (to be solar powered)

I am trying to build a small contraption/artwork to be mounted on a wall indoors. Ideally it will solely solar powered from a small solar panel (10cmx10cm). It needs to spin slowly anywhere between ~...
1
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1answer
56 views

Energy Harvesting Primary VDD and Battery Backup VDD power for MCU

Currently I am in the design process of circuitry for my energy harvesting circuit. I am using the CC1110F32 MCU from TI. I am using the Development kit boards that they created for this project. The ...
1
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2answers
95 views

Very low power voltage regulator - diode?

I'm developing a very very low power system, and it has some components that need 3.3V. These components are actually spec'd to operate anywhere between ~1.8V and 3.7V, so theres some wiggle room ...