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Creating a simple electronic circuit for the first time can be an intimidating experience. Many things can go wrong, including overheating the circuit and destroying electronic components. Fortunately, it is possible to create a simple electronic circuit, such as a light-emitting diode (LED) that turns on and off, correctly the first time by following some basic guidelines. Before building a circuit, every hobbyist should understand what a schematic is and how to read it, have the right tools, and know how to solder.
A schematic shows how electronic components are connected in an electronic circuit. Like a map, it uses symbols to represent components, such as resistors and capacitors, and lines to show how those components are connected to one another. When reading schematics, beginners should pay special attention to polarized components, which are sometimes marked with a plus sign or line on one side. Unlike other components, polarized components contain an anode, in which the positive current flows into the component, and a cathode, which allows the current to flow out. Polarized components, such as LEDs and some capacitors, must be installed with their anodes and cathodes in the right tracks, as indicated by the schematic.
Before building a simple electronic circuit, confirm that the schematic is accurate and generate a list of required components. Schematics in books and on popular hobbyist websites tend to be accurate. When using one from the web, choose a schematic that has been reviewed positively by other hobbyists. Once its accuracy is confirmed, generate a parts list by writing down the names and values of every component in the electronic circuit.
It is generally a good idea to keep a digital multimeter in the workspace. This device tests the properties, such as resistance and the flow of current, of electronic components and circuits. If a component's value is not easy to determine, a multimeter will provide an accurate answer. For example, if a resistor's value is unknown, set the multimeter to read Ohms, probe each end of the resistor, and read the value that appears on the multimeter's screen.
A breadboard and clamp should also be in the workspace at all times. A breadboard is a tool used for testing circuits before they're soldered to stripboards or printed circuit boards (PCBs). It is generally a good idea to build a circuit on a breadboard before soldering it to the circuit board to check for errors in the schematic and malfunctioning components. When the circuit is ready to for soldering, use a clamp to hold the stripboard or PCB in place. This can decrease the amount of time it takes to solder and makes it easier to solder accurately.
People who are new to soldering should practice soldering inexpensive components, such as resistors and capacitors, to stripboard before soldering a simple electronic circuit. The soldering iron should always be fully heated prior to use, and its tip should be applied to the copper track briefly before the solder is applied. Many soldering irons provide a signal, such as an LED that turns on or off, when they are fully heated.
Components that are sensitive to heat should be soldered quickly or last. Diodes and microchips are two types of heat-sensitive components. For microchips, integrated circuit (IC) sockets can be soldered to the board in their place. After the IC sockets have been soldered to the board, the microchips are placed in their sockets. This also makes it easier to replace microchips that fail, since they don’t need to be desoldered.
An electronic circuit should never be worked on while it is powered. Doing so can result in electrocution and damage to the electronic components. Once the simple electronic circuit is built and ready for testing, the power supply can be attached. If the powered circuit produces smoke or a burning smell, the power supply should be disconnected immediately. If it doesn’t produce smoke or a burning smell, testing can continue.