Other Tools
Introduction
Many other tools find uses in a lab, such as power supplies, rework tools and multimeters. Each has an important part to play in board bring-up and testing.
Power Supplies
A power supply allows flexible supply of power to a board. It allows the voltage to be varied, typically from 0 to 30 volts.
However a good power supply also allows the maximum current to be set. This means that the supply will not apply more current that specified, even in the event of a short-circuit on the board. This is useful for board-bringup since it avoids the situation where a short-circuit can cause very large currents which destroy a number of components on the board.
Common voltages used by embedded systems are 3.3, 5 and 12. For many chips,1.2, 1.8 or 2.5 volts are also used, although these often have their power supply built on the board.
Rework Stations
A rework station allows boards to be 'reworked', removing, replacing and inserting chips. This is useful when a chip does not work as expected, or has been incorrectly placed by the prototype manufacturer.
While a soldering iron and solder sucker are usually sufficient for older through-hole components, most modern embedded boards make use of surface mount technology. Newer BGA technology is becoming more common as well, and a rework station is of some use with this as well.
A rework station can heat up all the pins of a chip at once, allowing it to be removed and inserted easily and with the minimum of disruption to the test of the board. It has nozzles for different types and sizes of chips so the right tool for each job can be used.
While a rework station requires some skill and practice, it not particularly difficult to use. With a little practice it is an invaluable tool.
Multimeters
A multimeter, as its name suggests, allows metering of various aspects of a circuit, including voltage, current, resistance and others. A good set of probes is essential to reach into hard-to-probe areas and to grab onto the various connectors available on a board.
Multimeters can measure large ranges with good accuracy. For example, one of our multimeters can range from around 1 microvolt to 1000 volts with better than 0.1% accuracy, and from 0.1 Ohms to 500 MOhms with up to 0.05% accuracy.