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Capacitors voltage

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Frank tech

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I am building an fm transmitter that will run at 12 volts. I need lots of capacitors. Do they all have to be 12 volt.

Ex: does a 10pf capacitor have only one universal voltage rating or do i have to get a 10pF, 12 volt one?
 
The voltage of the capacitor must be larger than the running voltage around its terminal, so you can use 13V or 30V, but not less than 12V, because if the cap's rating voltage is 9V and you supply it with 12V, it needs to be charged untill 12V and, its capacitance is just 9V at its uFarad, so it will blow up.
 
I am building an fm transmitter that will run at 12 volts. I need lots of capacitors. Do they all have to be 12 volt.

Ex: does a 10pf capacitor have only one universal voltage rating or do i have to get a 10pF, 12 volt one?



If I may try to interpret your question:

The voltage rating has nothing to do with the capacitance rating.

The voltage rating is the maximum suggested voltage the capacitor will tolerate before arcing, shorting or otherwise cease being a capacitor.
 
There are MANY FM transmitter circuits on the internet that DO NOT WORK or work very poorly. If it is built on a breadboard then it also WILL NOT WORK, a pcb or a compact stripboard layout is needed.
Most FM transmitter circuits are illegal because they cause radio, TV, and communications (police, ambulance, fire department and airplane controllers) interference.

12V is too high for an FM transmitter.

Post the schematic and we will tell you how good or how bad it will work.
I designed and built an FM transmitter that works fairly well. Its output power is low enough and its waveform is clean enough so it does not cause interference.
Most of its little low value ceramic capacitors came from old AM-FM portable radios and their voltage rating is 50V or 100V. My transmitter is powered from a little 9V battery and it can transmit farther than 2km to a sensitive home stereo or car radio.
 
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