Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

BNC and Voltage probe difference

Status
Not open for further replies.

alimjoco

Member level 4
Member level 4
Joined
May 22, 2011
Messages
68
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,286
Activity points
1,805
Guys,

What should be the difference If i used a BNC cable(50 ohm terminated) vs. a typical voltage probe(1M) in measuring AC signal??
 

Usually low impedance is used for current signal. High impedance is used for voltage signal.
 

so if im going to measure very low AC voltage signal, its more approriate to use a 50 ohm terminated BNC..oscilloscope should also be 50 ohm input terminated..End termination perhaps...
 

so if im going to measure very low AC voltage signal, its more approriate to use a 50 ohm terminated BNC
Not particularly. More interesting parameters are source impedance and signal bandwidth. Matched 50 ohm signal transmission achieves a flat frequency characteristic and resistive load up to GHz frequencies. It's sometimes used at low MHz frequencies, e.g. because instruments are provided with 50 ohm matching, but it's not general necessary. The most serious problem is, that your circuit must be able to drive 50 ohm. if it's not designed for 50 ohm matching , it most likely won't. Also in high frequency circuits, you can't simply attach a 50 ohm load to a circuit node without affecting circuit operation. So probes with resistive divider (500 to 5000 input resistance) or active probes with built-in amplifier are used to probe high frequency signals (almost) undisturbed.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top