USB Boost Single Multi Power Kit assembly

multiple power supply module connected

One of my projects (AVR DDS 2.0) requires multiple power supply that could supply +12V, -12V, and 5V. Back then I have constructed simple transformer based power source with few linear voltage regulators. It works fine, but is powered from mains 220V which is not safest solution to squeeze in to box enclosure. Other option was using ATX PC power supply, but it is too big. Banggood have been offering pretty neat power supply kit which has voltage boost circuit which rises voltage level either from USB or from 5-24V jack. Power supply kit has most of voltages that you may need including + 12V, -12V, + 5V, -5V , and +3.3V. It is capable to output 300mA per channel. Total power is limited to 10W which is not bad and can provide short-term high current single output, but be sure to attach included heat sinks in order to protect …

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Electrical signal power and energy calculations by example

In electronics and signal processing you have to deal with electrical signals. In many cases you may need to calculate signal power and energy. –it is easy with DC In standard situation when DC power supply is applied to known resistor or other device like LED, motor you can calculate its power very easy by applying Ohms law: If we rung this device for time T then we can calculate total energy used: In some cases you may not know the resistance of your circuit. In this case you can measure the current flow. So your power formula can be transformed by using same Ohms law:

Benefits of using multiturn potentiometers

Potentiometers are common electronics components that convert rotary or linear motion in to change of resistance. They can be found anywhere where some adjustments are needed, volume control and joysticks. You can dive in to long theory about potentiometers how they are made, what materials are used and what output characteristics they have regarding to rotation angle. As electronics hobbyist and probably pro you usually deal with two common types of potentiometers – basic pots with knobs and trim pots. First group of potentiometers are used where user has to access potentiometer when he needs to change one or another parameter like sound volume or screen brightness. They normally are bigger in size and can be mounted vertically or horizontally to board. Also they have a panel mount with nut. This type of potentiometers needs to be mechanically stronger and resistive material more durable due to frequent use.

Building simple constant current power LED driver

Normally when we need to drive low power LEDs we don’t care much about power losses. What we do we add a current limiting resistor and that’s enough. For instance for 20mA LED we choose between 300Ω-1kΩ resistor when powering from 5V. But different situation is with power LEDs. The currents are much bigger here like 1A and more. Adding resistor to limit the current isn’t an option, because power losses become significant. Here you need a constant current driver to drive it safely without wasting energy. It happens that I have Cree XR-E Q5 XLAPM-7090 LED lying around. It requires 3.7V driving voltage and can take up to 1A current. There are several light intensities given at specific currents:

Driving LEDs – things everyone needs to know

Light Emitting Diodes more frequently known as LEDs are semiconductor devices that converts electricity in to light. It hard to fond a gadget or other device that doesn’t use LED diodes. They are cheap they are simple to use and they are small. LEDs can emit different light color depending on different chemical compound material in a semiconductor. LED symbol One and common LED symbol is as standard diodes but with couple arrows indicating that it emits light:

Zener – one diode for many uses

Zener diodes are specially designed diodes (heavily doped) that have low reverse voltage breakdown. Due to this characteristic zener diodes are connected backwards to normal operation. If zener is forward biased it acts as regular diode with forward voltage drop at 0.6V. Zener diod backward voltage breakdowns may range from 2.4V up to 100V. Truly speaking if you need like 1.2V then probably you need to connect two forward biased diodes in series for 0.6V+0.6V = 1.2V drop.

Diodes – how to choose one

Diodes are semiconductor devices commonly used for many purposes. In generally you can imagine diode to be a valve that passes current to one direction and stops it to flow back. First thing that comes in mind – this might be a good choice for reverse voltage protection. In fact they are. But… In reality things are a bit different. First of all diodes aren’t perfect devices. They have so called forward voltage drop which is about 0.7V for standard diodes. So if insert diode in to power supply, say 5V the after protection you will get 4.3V where part of voltage is lost in diode. If you wanna go this way – better choose Schottky diode instead which has a smaller forward voltage drop. Forward voltage drop occurs when diode is forward biased what means current flow from anode to cathode.