There must be hundreds of types of PIC on the market at the moment. If you have never used them before it can be difficult to pick (excuse the pun!!) the right PIC. To narrow down your choice, the first question to consider is - “Will I want to re-program the chip, or just write the program to it once?” For educational uses the answer is likely to be that you need the facility to re-program. This means you almost certainly want a “flash re-programmable” chip. These have chip designations with the letter ‘F’ in the middle - eg. 16F84 Those with ‘C’ in the middle are most often programmable once only. Next consideration is the use of an external oscillator as the ‘system clock’ for your PIC. Many (most?) PICs need such an external oscillator connected to them. The 16F627 family does not need this component as it has an onboard oscillator. This means one less component is needed in every circuit you build with a 16F627 compared to, say, a 16F84. Perhaps this advantage means that the 16F627 is a little more expensive than those PICs requiring an external oscillator, I hear you say! Well it isn’t more expensive. If anything, 16F627 chips are cheaper than other equivalent PICs. You will have guessed by now that my favoured PIC chip for ‘ordinary’ educational use IS the 16F627. Many articles and other sources refer to the 16F84 as THE standard PIC. Increasingly, this is being recognised as another example of the BC108 syndrome. Later offerings can do the same job better or cheaper. Most DT electronics teachers now know that the BC548 is more than a match for the BC108, and only about one third of the price. The same thing has happened to PICs.

Which PIC do I use?