A bunch of random questions...

1. I've got a bunch of capacitors with no uf rating or voltage marked on them, however, they're marked with [number]J (perhaps the J is for joules?). I need help identifying them, as I've got three main groups:
a) 6 of these about 1"x3/4"x1/2" dimensions, marked "683J [what looks like an 's' in the middle of an ellipse]" then on the next line "800 A05"
b) around 10 of these that look smaller than (a) but otherwise are almost identical, marked "333J (S)" (new line) "400 *L"
c) what I think is a red capacitor 1/2" square and about 2/3" thick marked "2A374J"

Are the 'J' ratings voltages or capacitances or something else?

2. I don't know what these parts are, but I've got a bunch of various colored components that look basically like square plastic boxes with leads coming out of one end. I don't know much about electronics, so I don't even know what type of part these could be, however, a lot of them are marked:
a) Red one marked 9201-05-20 (newline) COTO-8837
b) Black one marked "Omniron Japan (newline) G2VN-234PH-US (newline) 12VDC" on top, "2312D9" on one side, and "Contact USA 120VAC (newline) 1.5A 30VDC (newline) Coil: 12VDC" on the opposing side
c) Small white one marked "1J63" on top
d) Grey one marked 3u2J50 on top, "9737 (newline) EVOX (newline) MMK" on the side

3. How do I place capacitors in such a way that their voltages are added (eg.- if I have 2 50V caps, should I put them in series or parallel for 100V)? Also, is there any way to place the capacitors together and increase voltage without increasing capacitance (eg.- putting 2 50V 1uf capacitors so that I get 1uf 100V, instead of 2uf 100V)? Also, if, for example, I have 3 50V capacitors connected in series/parallel (whichever increases voltage), could they be charged with a 50V power supply and yet when discharged together output 150V?

4. I've got an inductor that has 8 loops wrapped around this (estimating here) 3/16" ferrite thing, could I use this as an inductor for an FM radio? Also, what's the difference between FM and AM radio?

5. What's the formula for the output frequency of a 555 timer (in Hz)?

6. Where can I buy cheap, high voltage (5-15kV) capacitors? I think I'm going to need them to make a tesla coil or coilgun (or maybe a tesla coil powered coilgun :twisted:[/b})

7. What are some of the most commonly used ICs and what do they do (the next time I order parts I'm going to try to stock up because not having the right IC is really annoying)?

Thanks in advance for whatever help you decide to give me

I THINK I know the answers to most of your questions, but I'm not 100 percent sure, so I'll just answer the ones I know foresure.

1. This site tells how to read the code on the capacitors:http://xtronics.com/kits/ccode.htm ...hot. Maybe someone could explain this better.

1. a. 683J = 68000pF +-5%
b. 333J = 33000pF +-5%
c. 370,000pF +-5% ?
The letter is the tolerance, K=10%, J=5%, F=1%
2. Probably relays. If you put the part number into a google seach, it may come up with a data sheet.
a. Don't know
b. Relay, 12 volt coil, contacts rated for 1.5 amps at 120 volts or 30 volts DC.
c. ?
3. The voltaage of caps in series add but you should put a resistor across each so the voltage divides equally. Look up voltage multiplier circuits.
5. The LM555 or NE555 data sheet tells how to compute frequency.

Question 2a - Most likely a relay, marked Coto (relay manufacturer)
Question 2b - Definitely a relay, marked Omron (relay manufacturer) also has part number for Omron relay
Question 2c - don't know
Question 2d - Probably a capacitor - 3u2j50 probably the value/voltage, 9739 probably date code (37th week, 1997)


With both types of radio, a radio frequency carrier wave is used to convey the information. In AM radio, the amplitude (level) of the RF carrier is varied (modulated) in proportion to the information it carries, which can be voice, music, video, etc., thus the name amplitude modulation (or AM for short). In FM radio, the frequency of the RF carrier is varied (modulated) in proportion to the information being carried, thus the name frequency modulation (or FM for short).

Russlk,

question 3,

heres the formula.

caps in series Ctotal= 1/((1/c1)+(1/c2))

caps in parallel Ctotal = C1+C2


question 7:

it depends on what your doing, if you just want to learn then i'd recomend some logic gates frgho the 74hctxxx family