Capacitor Rating Question

wharf rat

wharf rat

Well-Known Member
I stumbled into an old Sears tube amp and am going to use it as a learning project. I want to recap it and am confused about reading the parts list.

How does one determine if a cap is Mica, Ceramic, or Paper?

Also, the part list has the rating, for example, 10000. Nothing else.

One has 180 N750 10%.

I've looked around and haven't found anything that makes much sense. Can someone steer me? Thanks.
 
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I am not sure about the 10000 number, unless it stands for 10000pF, or 0.01uF. The second number means that the cap is 180pF and has a negative 750ppm temperature drift. 10% is the tolerance of the 180pF number. That cap is likely a ceramic. Leaded ceramic caps often look look a flat disc. They can also be small ceramic tubes with wires wrapped & soldered around the metallized ends. Mica's are usually small dark brown rectangles. Markings are often in white or silver paint. Paper caps are larger cylindrical caps with an axial (usually) wire lead coming out of each end. They typically have the capacitance and their working voltage listed on them, either in print or else with colored bands on a black body. There are also ancient ones that look like cardboard tubes dipped in wax.
 
egellings said:
I am not sure about the 10000 number, unless it stands for 10000pF, or 0.01uF. The second number means that the cap is 180pF and has a negative 750ppm temperature drift. 10% is the tolerance of the 180pF number. That cap is likely a ceramic. Leaded ceramic caps often look look a flat disc. They can also be small ceramic tubes with wires wrapped & soldered around the metallized ends. Mica's are usually small dark brown rectangles. Markings are often in white or silver paint. Paper caps are larger cylindrical caps with an axial (usually) wire lead coming out of each end. They typically have the capacitance and their working voltage listed on them, either in print or else with colored bands on a black body. There are also ancient ones that look like cardboard tubes dipped in wax.
Click to expand...

Thanks. This kind of makes sense. It gives me a starting point. Will move slowly. Will post if(When) I have further questions.

Also, thanks Avionic. I do not have a service manual....hopefully soon.
 
Sears equipment is most commonly made by other manufacturers. If you can figure our who built it, you might find a manual for it. If you start a new thread with pictures, someone might be able to identify it - Chris
 
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