| Component
| Example
| Circuit Symbol(s)
| Application(s)
| How it works
| Cost /GBP
|
| 470 Ohm Resistor
| 
| 
| Used in series with LEDs to prevent current flow exceeding 20mA and blowing both the LED and the PIC. The PIC can only source about 20mA per pin.
| Resistors limit current flow. Apart from the resistor's value in Ohms you need to be aware of it's max power rating in Watts. Remember: R=V/I.
| 7p
|
| 10k Ohm Resistor
|
| 
| Used as a weak pull up resistor in switch circuits and timed R/C.
| Resistors limit current flow. Apart from the resistor's value in Ohms you need to be aware of it's max power rating in Watts. Remember: R=V/I.
| 7p
|
| 4.7k Ohm Resistor
|
|
| Used in R/C oscillator to control PICs clock speed.
| When a capacitor is discharged, it's recharge time will be dependent upon the value of the resistor in series with it.
| 7p
|
| 22nF Capacitor
| 
| 
| Used in combination with a resistor as an oscillator for the PIC. Also used in R/C timing circuits where the value of R is in question.
| Capacitors store charge on two plates separated by a thin insulator or, dielectric.
| 13p
|
| LED (light emitting diode)
| 
| 
| Visual indication that the PIC is performing its task.
| LEDs emit visible light (while still performing their role as diodes).
| 10-99p
|
| LDR (light dependent resistor)
| 
| 
| Used to detect light levels. Very high resistance when in darkness.
| The resistance cannot be measured directly by our PICs. Instead the LDR is linked in series with a capacitor, forming an R/C circuit. The capacitor charge time tells us the current resistance value.
| 1.40
|
| mini DIL switches
| 
| 
| Useful for setting inputs to circuits, where controlling their behaviour is the final job in contruction, rather than at a user level.
| Action is similar to normal switches - ie noisy! Don't expect clean switches between on and off: allow for the switch to 'bounce' within your PIC software.
| 99p (4 way)
|
| Battery Pack
| 
| 
| A simple way of saving a load of heart ache. Balancing, taping or soldering leads to batteries is boring.
| The PIC requires a maximum of 6v.
| Box 40p, Batts, 4.00
|
| PICs 16F84, 12C509
| 
| 
| You're gonna need some PICs to play with. The F84 is reprogramable and a powerful little beast. The 12C509 while a one-shot device (unless you go for the UV eraseable types), is very simple to program and interface. It's internal oscillator is very attractive to new PIC users.
| A self contained micro computer system in a single package. What more could you ask for? They've even made i/o easier for us!
| 2.00
|
| Fly leads
| 
| 
| Tinned to aid insertion, taking the time to create these will save plenty as you work.
| Single sided boards are almost certain to require a few extra leads to join components.
| 25m=1.50
|
| Soldering Iron!
| 
| 
| If you want to make any of your circuits permanent you're going to need one of these. Electric or gas powered. There is nothing much to fear about to soldering - if you get the joint properly hot, the solder will magically flow into exactly the correct position.
| Cheaper ones available which run on butane gas, otherwise tip heated by electric element.
| 10.00-50.00
|
| Prototyping board
| 
|
| A very useful test area for new circuits. Gives instant results for new PIC users.
| Plugblock of 600 contacts made up from: 4 blocks of 25 rows of 5 interconnected sockets.
| 13.00
|
| Piezo Transducer
| 
|
| Small, flat and within their ideal frequency range can be quite noisy. Get ones with pre-soldered leads if possible as you can break them easily with the heat of the iron. Mounting position has large effect on sound output. Drive from rapid on/off signal on a pin.
| Use the piezo electric effect, whereby a crystal can be made to resonate via an electrical signal. (In this case a 3V square wave).
| 40p
|
| Power MOSFET
| 
| 
| Transistor that operates on voltage rather than current. They take so little current at their gate pin that you can connect them directly to a PIC with no current limiting resistor. However they can drive *huge* currents (++Amps) across their drain/source pins. Note: Tie their gate down to 0v via resistor for best results. Also note, the gate voltage should be as high as possible (+10V) to get maximum voltage across the load. In common with other MOS components they are static sensitive.
| Field effect transistors operate on voltage, drawing almost no current whatsoever. This fact is underlined when you consider that the gate of a MOSFET is actually insulated from the rest of the device by a thin layer of silicon oxide.
| 1.35 for BUZ10
|
| Transistor (NPN)
| 
| 
| Use in low power switching/amplification applications. Limit base current with resistor.
| Transistors are created from an NPN or PNP semiconductor junction.
| 30-60p
|
Programming
