Filter capacitors reject unwanted frequencies.
Frequency filters are electronic circuits that determine which frequencies pass through the amplification stage of an audio device. A bandpass filter is a static frequency filter. While a dynamic filter such as an equalizer permits you to adjust the frequency filtering parameters, a bandpass is set to a fixed range. S-band refers to the range between 2 GHz and 4 GHz. You can modify your existing audio equipment to receive only frequencies in the S-band range, by building an S-band bandpass filter circuit.
Instructions
1. Mount the blank circuit board in a bench-clamp, or bridge it across two books to elevate it at least 2 inches off the work surface. This prevents the capacitor and inductor connector pins from getting squashed when you populate the board.
2. Color-code the schematic -- the document that illustrates the layout of, and relationship between, the capacitors and inductors. This way, you can quickly cross-reference your work when populating the circuit. Mark each component in its own color, using colored-marker pens, then use the same color to mark the relevant turret on the circuit board and the symbol on the schematic.
3. Mount the filter capacitors, inductors and coupling capacitors onto the blank circuit board. Refer to the color-coded schematic to determine the correct turret for each component. These are the integral components for an S-band bandpass filter. The filter capacitors in an S-band bandpass filter reject frequencies outside the 2 GHz to 4 GHz range. The inductors store an electrical charge, which drives the signal received by the filter circuit to the amplification circuit.
4. Push each board-mounted component into its turret, with sufficient force to drive the connector pins through to the base.
5. Remove the board from the clamp, flip it over and reattach it so the connector pins are facing up.
6. Push down gently on each connector pin, so it lies flat against the copper stripe on the base of the board. This stripe is the board's conductive pathway. The signal passes along this pathway, between the filtering components. Circuit boards with stripes eliminate the need for wired connections.
7. Put a small amount of rosin-core solder onto the the tip of a hot soldering iron.
8. Press the iron against the connector pins and copper stripe simultaneously, to fuse the component to the board.
9. Remove the board from the clamp, and place it on a flat surface.
10. Cut two pieces of 1-inch power wire. Strip approximately one-eighth inch from the tip of each wire.
11. Solder a wire to the input terminal of each RCA jack. Solder the loose end of one wire to the leftmost board eyelet. Solder the other to the rightmost board eyelet. The jacks enable you to connect the filter circuit to external devices, such as radio receivers and amplifiers.
12. Screw the RCA jacks onto the side of the blank circuit board, in the predrilled mounting holes.
Tags: bandpass filter, circuit board, connector pins, blank circuit, blank circuit board