Precision circuit monitors negative-supply threshold: [via]
Using an IC (MAX971) that includes an open-drain comparator and a precision 1% voltage reference, this circuit monitors the magnitude of a negative supply voltage and provides a digital warning of fault conditions. To monitor multiple negative voltages, use the MAX974, which includes four comparators.
App note: Monitor negative power supplies – [Link]
Here is a simple and economical 10A variable power supply with 1.2-30V. LM317 have been used to drive 3 NPN TIP41C transistors (or three 2N3055). Nothing to say about the project, it is really simple. The main supply must be connected to a rectified source (transformer + 20-30A bridge rectifier). For Q1,2 and 3 can be used any power TO220 transistor (TIP132C,TIP41C etc) or three external 2N3055 transistors. [via]
10A 1-30V Variable Power Supply with LM317 - [Link]
Power is an important aspect of all embedded systems. Nothing works without electric power. Depending upon the type of applications, several options for power are available. For example, if the system doesn’t need to be portable, it can be powered directly from the wall source using AC adaptors.
Regulated power supply for embedded systems – [Link]
Here’s a little bench power supply I made using the Adafruit Power Supply kit. I just replaced the kit’s PCB mount potentiometer with a panel mount pot and added a 7805 5v regulator to power the display. The acrylic panel was made from a scrap piece I had and the heat sink came from a dead PC power supply.
Variable Power Supply – [Link]
This project shows how to measure the power supply of your micro-controller that can be very important and critical, specially for battery powered applications. The solution the author explains in this short tutorial don’t need any external components, for all the AVR micro controllers that have an internal ADC. As an example in this article, we are going to use an ATMEGA48 micro controller.
AVR: Monitor power supply voltage, for free! – [Link]
This is a simple dual power supply using voltage regulator IC 78xx and 79xx series. It’s the best and simplest choice for most non-critical applications. The 3 terminals are input, ground and output. The 78xx & 79xx series can provide up to 1A load current and it have onchip circuitry to prevent damage in the event of over heating or excessive current.
Dual Power Supply 78xx-79xx series – [Link]
This project is an adjustable voltage bench power supply made using a ATX PSU. The author added a control panel providing connections to various voltage levels and he added an Ammeter and Voltmeter to display output values. He also added a MIC29152WT adjustable voltage regulator so that the output voltage can be adjusted. [via]
Adjustable voltage bench supply using a ATX PSU - [Link]
Rhys Goodwin @ rhysgoodwin.com wanted to automatically start up his GPS unit when he turn the key of his car. To achieve that he should apply 5 volt to pin 6 at the base connector of the Ipaq. In that way the Ipaq wakes up. This seems easy to do but that method has some problems. To manage these problems Rhys Goodwin rebuild the power supply with a 10 sec delay on the output to Ipaq using a circuit found online.
Ipaq Auto-wake for in-car Application – [Link]