BREADBOARD POWER SUPPLY
The board has two modes of power input. Through USB and through a DC barrel socket. There is a green LED to indicate the presence of powerand a latching switch to control the power to the board.
The operating instructions state: Input voltage to be between 6.5~12Vor USB powered (5V). Hence if you wish to use it to its maximum capability you will need to remain in that range. This is a non-adjustable power supply model and the output voltages are fixed to 5V and 3.3V which is good enough for most applications. The maximum output current is stated as 700mA. Howeverif you’re not experienced enough in electronics it is probably better to use much lower voltages and current than the stated to be on the safe side in case you make a mistake on your breadboard circuit. A breadboard project with a single chip and a transistor will normally work fine on very low currents.
Voltage Regulator AMS1117 Spec: The circuit is based on a pair of AMS1117 voltage regulators by Advanced Monolithic Systems. One is used for creating a 3.3V rail whilst the other for creating the 5V rail. These are actually quite a good make of components to be found in a SOT-223 package. Their datasheet states that this series can provide a maximum output current of 1A. The absolute maximum voltage rating is 15V at the input. Obviously you should not use these levels as this is the component rating.
The regulators datasheet also indicates that these components have a built-in protection against short-circuit through power limiting circuitry. There is also thermal overload protection circuitry which will shut-down the regulator should its junction temperature reach 165deg C.
These regulators also have internal diode protection and can handle transient surge currents between 50A – 100A.
This is a high efficiency low drop-out regulator which can operate down to 1V. It has a 1V input-to-output differential and therefore useful for battery powered applications. Line regulation is 1.2% Max and Load regulation 0.4% Max.
The AMS1117 series is an excellent choice for creating adjustable power supplies since it is designed for this type of application as well. The package provides a 1.25V reference voltage from the adjust pinand with a pair of resistors in a voltage divider network the regulated output can be adjusted. The PDF Datasheet is also very clear and comprehensive in its use.
SOT-223 package is quiet a largish one and if you are new to soldering SMD this might be the one to start out with. These are available at Amazon and ebay for as little as a Pound for ten.