Hi. I'm a physic teacher that have fun learning electronic in order to make some projects with kids. I bought Dave cutcher's "electronics cricuits for evil genius".
When learning transistor, i have not problem with NPN theory and practice but with PNP, i understand the theory but the practice isn't working: if i breadboard the "lesson 10", it simply didn't work!
Here it is :
It doesn't work! voltage on collector is 1 volt when the switch is not push and it is suppose to lit on the led on power ON and power slowly off the led when pushing the switch. Even removing R1, R2 and C1 and the switch, the transistor is suppose to lit on the LED. The theory said that PNP transistor is an open valve until some pressure is on the base of the transistor (opposite of 2N3904 that on power on the LED is off and need voltage on the base to on the LED). I have sevral 3906 and they all do the same.
What is my mistake - or perhaps it is the book?
When learning transistor, i have not problem with NPN theory and practice but with PNP, i understand the theory but the practice isn't working: if i breadboard the "lesson 10", it simply didn't work!
Here it is :
It doesn't work! voltage on collector is 1 volt when the switch is not push and it is suppose to lit on the led on power ON and power slowly off the led when pushing the switch. Even removing R1, R2 and C1 and the switch, the transistor is suppose to lit on the LED. The theory said that PNP transistor is an open valve until some pressure is on the base of the transistor (opposite of 2N3904 that on power on the LED is off and need voltage on the base to on the LED). I have sevral 3906 and they all do the same.
What is my mistake - or perhaps it is the book?