Tagged Questions

1
vote
1answer
59 views

Wiring a switch to toggle both usb power and external power on Arduino

I have a 5v Arduino Pro Micro. I am using it to run a series of motors. I am controlling it through the USB port. The USB power doesn't supply enough current to power the motors, so I am using a 9v ...
1
vote
2answers
107 views

How to connect a DC socket to a switch

I have a basic flip switch that I want to use to control whether a DC power socket is providing energy (from a connected battery pack). The power socket has three prongs, the switch has three, and ...
4
votes
2answers
531 views

How to properly switch between two power sources with a MOSFET?

In our application, our board can receive +12V from an adapter jack when working in standalone mode. This 12V is fed into a switching regulator to create a 3.3V supply (named 3V3_2 in the schematics ...
4
votes
2answers
200 views

Switching a Large Current with a Tiny Switch

I have a SPDT switch that can switch .3A @ 5V. I would like to use it to switch 1A @ 9V which will then be fed into a 7805 linear regulator. This is the design that I have come up with. I have run ...
6
votes
7answers
1k views

How can I turn on and off a switch every 20 minutes?

I want to make the above switch which will stay on for 20 minutes and then off for 20 minutes. This should be continuous. Actually, I want to place this switch for my air conditioner which I do not ...
2
votes
2answers
2k views

Add on/off indicator LED to circuit

I'm working on my first small electronics project; building a small LM317 based power supply. I've built the circuit as shown in the data sheet (black part of the circuit diagram below) on a ...
0
votes
1answer
286 views

How could a charger “cut out” when charging is complete? [duplicate]

Possible Duplicate: Why is it so problematic to have close to zero standby power consumption? How would you detect vampire/standby power? This article discusses why cell phone users have ...
2
votes
3answers
938 views

Switching 120V AC with Digital Logic on Isolated Power Supply

Context: A digital phase-controlled light dimmer system. 120V AC mains I use an isolating transformer (and rectifying circuit) to generate +12V and +5V DC rails. I want to use reverse phase ...
4
votes
4answers
2k views

how to build a low-voltage disconnect switch for DC 12.4V 70A?

How can I make a device that will make the power connected as long as the voltage of the power-supply keeps over 12.4 V (adjustable) and disconnect it if it falls below? It also must connect the ...