> Hi Richard, > > Just to give you some comfort, I have recently bought a used Oscillescope (Leader Brand; LS 8106). It did not comes with probes. I bought 2 brandless probes from regular electronic store that has a pin, a clip and a x10 switch (x10 is relevant if your scope is 100Mhz). At the other end of the cable is a BNC connector. According to the shop keeper, BNC connector should be universal (since I'm new to EE, I am not sure about this though). Thus, a probe can be used on most brands and types of oscillescope. I've been watching some of the scope probe discussions. I may have missed somebody else making this point but it is important that you have sufficient bandwidth rating in the probe for the oscilloscope's input bandwidth. A few points about oscilloscope probes. First, most "modern" oscilloscopes use BNCs as their input port. Some very old models used banana or pin jacks. Some newer units use SMA or SMB, particularly those intended for use in PCs or other chassis. Of those that use BNCs there are some out there with an extra ring of metal at the base of the BNC. Looking closely at OEM probes for those instruments you will see a little spring loaded pin. Plug on the probe and the pin makes contact with the ring. The simplest of these use a small resistor inside the probe BNC housing to indicate x1, x10, x100, etc range of the probe. Second, all x10 and x100 probes I've dealt with have an adjustment (and sometimes 2) for tweaking their capacitance to match that of the oscilloscope input. Learn how to make this adjustment. Do it each time you reattach the probes or if you think somebody else has been using your oscilloscope. Third, bandwidth and rise time of the complete system, probe tip to CRT, can be estimated by adding risetimes as the sum of squares. 1) Bandwidth of oscilloscope = 100MHz. Rise time will be rt=0.34/F3dB This is approximate assuming the oscilloscope has a Gaussian response. And before anybody jumps on me for using only two digits, this is just for illustration. Use 0.338 if you like or more digits. Or if you want to assume the oscilloscope bandwidth is given as its equivalent noise bandwidth, use 0.361 instead. Anyway, the rise time is about 3.4ns. 2) Bandwidth of oscilloscope probe at x10 setting = 100MHz. Its rise time can also be reasonably approximated by 3.4ns. This would be a dirt cheap, junker probe. By the way, if you have a switchable probe, the x1 range may be as low as 6MHz bandwidth. 3) System rise time = (rt1 ^ 2 + rt2 ^ 2 + ... + rtn ^ 2) ^ 0.5 We only have two elements in our system so rt = (2 * (3.4 * 3.4)) ^ 0.5 = 4.8ns or about 71MHz The point of all this is you need to buy a good probe otherwise you are not getting good use from the oscilloscope. Some time in the future when you are trying to make some rise-time measurements or look at the skew of a signal, this can come back and bite you in the butt. From companies like TPI (http://www.tpi-thevalueleader.com/, no affiliation, just listing as an example) you can buy reasonably priced 300MHz x10 probes. Putting a 300MHz probe on a 100MHz oscilloscope keeps your useable bandwidth up around 95MHz. Just some of my pet peeves because I used to teach undergraduate EE labs and I don't know how many times I had to hold the student's hand and lead them through the oscilloscope manual because they couldn't read for them selves. Then later I worked for an oscilloscope manufacturer and had to listen to people complain that their measurement bandwidth was well below the stated specification. I found many polite ways to explain to them we could not break the laws of physics and that they needed to pay attention to what they were doing. I still feel there are few electronic instruments more mis-applied or more misunderstood than the oscilloscope and particularly the digital oscilloscope. If you didn't get a manual with your oscilloscope, try to find one! Also Tektronix wrote one of the best how-to application notes for oscilloscopes. Use Google to find a copy of "The XYZs of Oscilloscopes". The title may have changed to "The XYZs of Digital Oscilloscopes" by now since Tek doesn't make analog scopes anymore. If you can get past the fact that it is very Tek-centric in its illustrations and writing style, it is a VERY GOOD beginner's tutorial. Agilent (or Hewlett Packard as it was once known) had some good app-notes but I can't remember titles. Also companies like Nicolet, LeCroy, National Instruments and Gage Applied Science may have some good stuff on their web pages. Peeve has now been petted. It will sleep again. Rob Young -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.