Bench Test Equipment

[MP1]

Would like to see postings of used Bench Test Equipment. I think we all could use another meter from time to time.

MP

 

[Kevin Weddle]

I am thinking of purchasing an oscilloscope. But I think I want one of those brand new ones from Radioshack. It is has a single probe and it's the handheld type. Could you convince me of a cheap used oscilloscope?

 

[Kevin Weddle]

I found an oscilloscope on Ebay. It's a Madell 10 Mhz brand new. I am waiting for it to arrive. Does anybody know these oscilloscopes.

 

[MP1]

I purchased a madell power supply not long ago and found that the company imports directly from China. The banana jacks were smaller than the standard that is normally found on test equipment. I had to open the box and perform modifications from the start. You should ask the seller lots of questions about connectors for the leads and resolution.

MP

 

[Kevin Weddle]

I finally received the oscilloscope. It helps very much in determining pulses. I think I got a good deal as it was only $150. The thing get's very hot too. My only concern is the GND. It does not seem to do anything. Isn't it supposed to show a ground reference trace when GND is selected? Other that, I think the design of the thing is tried and true due to the overmanufacturing of the these devices. It is the crudest of oscilloscopes. What do you think?

 

[ante1]

Kevin,

It sure is a good help for determining pulses and such. I think $150 is OK for this scope. How hot is very hot and what is the source of the heat (power supply)? The GND switch just grounds the input as far as I know. It looks good but what

 

[Kevin Weddle]

I found the GND to give me a ground reference with respect to the signal. I knew it would work. The heat is from the power supply I feel. One of the first things I did was to test an opamp backwards. The gain setting resistors on the noninverting input to output. It worked. The only thing is when the signal is applied to the inverting input, I can't keep the bias. This makes sense because this is the only opamp configuration that you can have that will cause an increase on one input and a decrease on the other input. This pulls the difference far apart and you lose bias. I was able to get half the sine wave with this configuration but the other half was clipped.