Breadboards - How bad are they at RF? [Deleted]

[JimB]

JimB submitted a new article:

Breadboards - How bad are they at RF? - Over the years many threads have revolved around the poor operation of a circuit built on a breadbo

Over the years many threads have revolved around the poor operation of a circuit built on a breadboard, the type with lots of strips where components can be plugged in to make the connections.

The usual problem is when the circuit is expected to operate at more than a few kilohertz, strange things start happening.

When someone asks a question about this, all the experienced guys here will jump in and tell that the breadboard is totally unsuitable for use at "RF".
What I have never seen...

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[cr0sh]

Interesting; I wonder how a similar test with high-speed digital signal transitions (logic HIGH to LOW and back) would fare on say a microcontroller design using a PIC or ATMega...?

 

[JimB]

This resource has been removed and is no longer available.

 

[Sceadwian]

Simply; it would increase the RC time constant because the capactiance of a breadboards line and parasitic capacitance between lines is high, this can affect the function of the circuit it many ways. To intentionally design a circuit to work with these parasitic's is folly if not outright impossible. Design it in the environment it needs to work in permanently. Anyone that use a breadboard as permanent circuit is not designing properly.

 

[KennyP]

I want to thank you for restoring my sanity!!!!! I have been experimenting with many rf circuits. I'm very very low on money right now so each component is quite precious. One can only solder and desolder and make little snips here and there so many times before a component is rendered useless. Yes, its quite humbling and embarassing. I lost track of how many times my completed circuit left me scratching my head (and pulling each hair out of my head one by one). I checked an re-checked,re-calculated and everything else a person does when an rf circuit starts......well....ARFING at you!!!!!! Its quite strange that I started to think that using a breadboard might be causing me to loose my sanity and I decided to come here to post my problem. Wow!!!! Talking about perfect timing!!!!! Thank you thank you thank you thank you thank you for clearing things up for me and restoring my sanity.............for a little while. Maybe someday I'll be able to afford the necessary test equipment for rf design, but for now, JimB, the best info is free!!!!!!! Thanks again!!! KennyP

 

[JohnJ]

A very smart Engineer I worked with taught me how to use breadboards in higher speed circuits.
Each line has a finite capacitance coupling it to the next line. The trick is to alternately connect every second line to Ground and V+, then use the remaining connections for your circuits (i.e. row 1-gnd, row 2-use, row 3-V+, row 4-use, row 5-gnd, etc.). Be aware that there is just a piece of paper between the contacts and whatever it is attached to so an extra insulator (increase the gap) can help if you have signal losses. Also, bread boards wear out and corrode, replace them from time to time. I have used breadboards for circuits well over 100MHz using these techniques.