Hardware Hacking 65We will build our circuit on a breadboard. The breadboard is a system for
interconnecting electronic components without solder. On it you can prototype
and rearrange circuit designs quickly, without damaging components. It consists
of a plastic block with lots of little holes, beneath which are strips of wire
arranged in a matrix. These strips, called “buses,” run in one or two long
horizontal strips along the top and bottom edges of the block, and in numerous
shorter vertical strips that extend above and below a central groove.
The holes are the right diameter for the leads of most electronic components
(resistors, capacitors, integrated circuits, etc.) and hookup wire. Circuits are built
up by inserting components into the holes on the board and connecting them by
linking rows and columns of the matrix with short strips of wire.
Place the breadboard on the table so the trough-like central groove runs
horizontally, from left to right. Strip, twist & tin carefully 1/2” from the ends of
each lead of a 9v battery hookup clip. Insert the end of the red wire in one end of
the bus on the upper edge of the breadboard and the black wire in a bus along
the lower edge. Anything inserted in the upper bus will now be connected to +9
volts, while anything inserted into the lower one will be connected to ground (0
volts.)
Press a Hex Schmitt Trigger IC into the breadboard, taking care not to bend
over any pins. Observe the orientation of the notch and/or small dot as shown
in the schematic. Use a jumper to connect pin 14 to the +9 volt bus and pin 7 to
the ground (0 volt) bus.
Connect a 0.1 uf capacitor between pin 1 and the ground bus. Connect a resistor
of about 100kOhm between pin 1 and pin 2. Use clip leads and a short pieces of
wire to connect the tip of a jack to pin 2 and the sleeve of the jack to any point
along the ground bus. Connect the battery to its hookup clip. Turn on the
amplifier and listen (watch the volume -- this circuit is loud.) You should hear a
strident steady pitch, a square wave -- if not, check your connections.