Would you drive a 1930's automobile with NOS 70-year-old tires? How about using NOS (New "Old Stock") capacitors? These are not recommended…use at own risk! As paper and electrolytic capacitors age their capacitance values drift, they dry out and they become leaky.Modern film capacitors are non-polar, so you don't have to worry about polarity when replacing old paper caps with new film capacitors. The positive end must be kept at the higher electrical potential (more positive voltage). The flat side of the capacitor symbol is the positive (+) side and the curved side is the negative (-) side. Just be sure the capacitors you order have long leads. With "axial" type, there is a lead at each end of the capacitors.īoth types are equally good. With "radial" type, both leads exit from the same end of the capacitors. Capacitors have either "radial" leads or "axial" leads.Mica capacitors come in different sizes and shapes, but the most common shape is square or rectangular….brown in color with colored dots (sort of look like "dominos").They are usually 1 to 1 1/2 inches long and 1/4 to 1/2 inches in diameter. The original paper capacitors in your radio will likely be in a brown paper tubular case (sometimes coated with wax).With the lightweight AC/DC sets of the 1950's they are quite often under the chassis and may have a cardboard case. On the old AC sets they are usually encased in aluminum and mounted on top of the chassis.
The original electrolytic capacitors are typically the size of a roll of quarters or larger.
Size wise, the electrolytics are the largest capacitors and most tube radios use 2 or 3 of them. If it is between 0.001 uF and 1.0 uF it is likely a paper capacitor and if it's more than 1 uF it's probably an electrolytic capacitor. As a general rule, if a capacitor in your vintage tube radio is less than 0.001 uF, it is probably a mica capacitor. You may want to tape this conversion chart to your workbench. When reading schematics and buying capacitors, you sometimes have to be able to convert uF to pF or pF to uF. For example, a mica capacitor valued at 500 mmfd (pF) would be 0.0005 mfd (uF). Short forms for micromicrofarads include mmfd, MMFD, MMF, PF and pF. Micas are expressed in terms of micromicrofarads (picofarads). The mica capacitors in your tube radio will have lower capacitance values than the paper and electrolytic capacitors. Short forms for microfarad include mfd, MFD, MF, UF and uF. In radio service parts lists and schematics, paper and electrolytic capacitors are usually expressed in terms "microfarads". When you restore an antique radio you will replace the paper and electrolytic capacitors, but not the variable and mica capacitors. Your old tube radio uses 4 types of capacitors: variable (tuning) capacitors, mica capacitors, paper capacitors and electrolytic (filter) capacitors. This is sometimes expressed as WVDC (Working Voltage Direct Current). The voltage rating is the maximum voltage the capacitor can handle without breaking down. The capacitance value is a measure of how much electric charge a capacitor can store. Capacitors have a capacitance value and a voltage rating. If you're not the best speller, a condenser, capacitar, capaciter, capacitor, condensar and condensor are also the same. Don't let terminology confuse you…."condenser" is just an old fashioned name for "capacitor". Capacitors are used to block, pass, filter and tune the various currents in your radio. Capacitors act to pass AC while blocking DC. Your vintage tube radio needs both direct current (DC) and alternating currents (AC) to operate. We hope you find this capacitor advice useful re your vintage radio repairs and restorations. #HOW TO ADD A CAPACITOR TO GROUND IN POWER WORLD SIMULATOR HOW TO#
How to choose capacitors and install them in tube radios is explained in non-technical If you are new to restoringĬAPACITOR TIPS. Capacitor Tips re Antique Tube Radio RestorationsĪBC's of Capacitors - Capacitor Tips for Tube RadiosĬAPACITOR TIPS for the beginner.
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