Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

negative resistance device

Status
Not open for further replies.

unclejed613

Well-Known Member
Most Helpful Member
when i was young, there were a lot of tunnel diodes being used in a lot of different applications. but through the years, tunnel diodes have just about disappeared, except for a few microwave applications. tunnel diodes have a negative resistance region in their forward conduction curve but usually only over a span of about 0.1V. Gunn diodes also have a negative resistance region, but most Gunn diodes are made specifically for microwave applications. however there's a device that can be made with a pair of JFETs called a "Lambda" diode. the device works well at frequencies up to the limits of the JFETs used.

negative-r-jfets.png

this allows some very simple oscillators to be built. shown here is a pair of JFETs (one N type, and one P type) and the forward bias curve. notice the very large negative resistance region, and that unlike tunnel diodes, the device goes into cutoff at voltages above the negative resistance region instead of the junction current rising. the shape and span of the negative resistance region can be changed by using different JFETs, the particular pair shown (2N5484 and 2N5114) gives a negative resistance region that begins at 1.9V and goes to about 9.5V.
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top