What’s the Difference Between PNP and NPN Transistors?
There are numerous differences between NPN and PNP transistors, and even though both are bipolar junction transistors, the direction of current flow is the name of the game.
Both are used in various amplification and modulating circuits; the most frequent among its applications is being fully ON and OFF, which is referred to as switch mode. It’s easy to remember that NPN stands for Negative-Positive-Negative and PNP stands for Positive-Negative-Positive.
Rise and Fall of Radio Shack and Heathkit
Radio Shack and Heathkit are long gone but these companies had a major impact on young engineers.These articles touch on the companies, their impact, and what happened along the way.
- Electronics Still Thrives as a Hobby
- Heathkit: A Right-Time, Right-Place Business
- The Shack Is Back
- Update: The Shack Is Back
- RadioShack: Tragedy or Inevitable?
- Radio Shack to Close Most Retail Stores
- Heathkit Closes, Again. This time for good?
- What’s Happening With Heathkit and Radio Shack?
- The Rise And Fall Of Heathkit—And Rise Of SparkFun (available as .PDF download)
- Have Chip Vendors Taken Over Where Heathkit Left Off?
- Heathkit: An Employee’s Look Back
Resistors: Types and Applications
An ohm is an ohm, right? Not so fast — there are many different types of resistors. To insure that your circuit works and stays working, use the right type of resistor. In this article, you’ll learn about the common types of resistors and their special characteristics.
Rob W4ZNG says
It seems that 40 years along in dealing with this stuff, still the only way I can tell one type transistor from the other in a schematic is NPN = “Not Pointing iN” which leaves PNP as “the other one.”
Dave, N8SBE says
Radio Shack and Heathkit were certainly staple items in my early ham radio days, which started in 1970, with an antenna built out of what I could scrounge at the nearby Radio Shack, and a Heathkit HW-101 I built from a kit when I upgraded from Novice in 1971. I was lucky to also have a Fayette Electronics store in town, and an Allied Electronics nearby.
Dave, N8SBE says
Radio Shack and Heathkit were certainly staple items in my early ham radio days, which started in 1970, with an antenna built out of what I could scrounge at the nearby Radio Shack, and a Heathkit HW-101 I built from a kit when I upgraded from Novice in 1971. I was lucky to also have a Fayette Electronics store in town, and an Allied Electronics nearby.