How to Make a Simple Circuit Board
A simple circuit board is used to allow a student or technician to study pieces of a circuit or to refine a circuit's performance. In each case, the components must be physically stable for convenient measurements and must be easily removed for current measurements or replacement. The circuit used for this discussion will have an input capacitor, three resistors in parallel, an inductor and an output capacitor. The reader can replace this circuit with one of interest, but the format will be the same.
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Things You'll Need
- Metal mounting posts 1/8-inch diameter by 1-inch length
- Fiberglass card (sometimes known as G10) at least 3-by-3 inches and at least 3/16-inch thick and "unclad" or having no copper plated on either side
- 2 capacitors 1 microfarad, 20 Volt
- 3 resistors 1K ohm, 1/4 Watt
- 1 inductor 50 micro-Henry
- Sharpie-type marking pen
- Diagonal cutters
- Needle nosed pliers
- Small hammer
- Small signal generator
- 12 Volt DC power supply
- Buss wire (24 - 20 AWG)
- Soldering iron
- Solder
- Digital Multi-Meter (DMM)
- Hand drill
- 3/32-inch drill bit
Instructions
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1
Using the diagonal cutters, trim each of the components (resistors, capacitors, inductor), leaving a metal lead of approximately 1/2-inch.
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2
Physically lay out the components onto the G10 board. Leave room around each component to allow use of a soldering iron and meter. Place the input capacitor at the center of the left side of the board, place the three resistors in parallel across the center of the board. Place the last capacitor parallel to the top resistor and the inductor parallel to the bottom resistor.
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3
Mark points on the board, using the marking pen, where the component leads end. Set the components aside.
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4
Use the drill and 3/32-inch bit to drill holes at the points you marked on the board.
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5
Lightly hammer (tap) metal posts into the holes drilled. The fit should be tight and the posts should show 1/2-inch below the board.
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6
Solder the components to the posts as you placed them in Step 2.
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7
Wrap buss wire around the right post (where it comes out underneath the G10 card) of the input capacitor and solder the wire into place.
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8
Stretch the buss wire to the underside of the left posts of the three resistors and solder the wire to each post.
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9
Clip the wire after the third resistor post. The right side of the input capacitor is now electrically tied to the left ends of three parallel resistors.
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10
Use buss wire soldered to the right end of the top resistor post (underside) to connect to the left post (underside) of the second capacitor and solder it onto the capacitor's post. The upper resistor and capacitor are now in series.
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11
Use buss wire soldered to the right end of the bottom resistor post (underside) to connect the left post (underside) of the inductor and solder it onto the inductor's post. The bottom resistor and inductor are now in series.
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12
You now have a simple circuit for testing AC and DC responses to pure resistance (center resistor), resistive-capacitive (top pair) and resistive-inductive (bottom pair) situations. Attach either the DC power supply or the small signal generator to apply AC and/or DC to the circuit. Voltage may be measured across any individual component by applying the DMM leads to the readily accessible posts.
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13
To measure current through any component (remove power and then) use the soldering iron and pliers to lift the component lead from the post where you wish to read the current. Restore power. Switch the DMM to current and clip one lead to the lifted component leg and the other to the post, placing the DMM in series into the circuit at that point to read the current flow through the component.
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Tips & Warnings
For circuit analysis, it is best to lay out the components to reflect the schematic you wish to test. It is simpler to visualize when the physical layout resembles the schematic. For circuit optimization, install your own test circuit using the techniques as described above. If (when) the circuit does not match the theoretical response, remove power, replace individual components with small value changes to move the actual response towards the desired goal.
Soldering iron tips are hot. Exercise caution when using a hot soldering iron.
