[ 3 / biz / cgl / ck / diy / fa / ic / jp / lit / sci / vr / vt ] [ index / top / reports ] [ become a patron ] [ status ]
2023-11: Warosu is now out of extended maintenance.

/diy/ - Do It Yourself

View post   
File: 28 KB, 1358x559, need help.png [View same] [iqdb] [saucenao] [google]
253435 No.253435 [Reply] [Original]

im trying to charge a HV capacitor using this setup but it wont charge, ive tried many configurations but I can't seem to get it to work? should i try using a bridge rectifier or what should i do? halp. thanks in advance

>> No.253468

>>253435
The diode in your diagram is backwards.

>> No.253470

>>253468

ive tried reversing the polarity of it, but it still wont work. i know i get a negative voltage from the output of the transformer though i dont know why i drew it that way

>> No.253475

The simpliest way would to be to just use a 4 diode bridge rectifier. Why use BJTs anyway?

>> No.253477

>>253468
doesn't matter as long as capacitor is hooked up to match

OP:
make sure the diode can handle HV
check diode
verify oscillator is working

>>253475
>simplest way
>4 diodes
as opposed to 1?

>> No.253483

>>253477
1) oscillator is working, im getting ~250v out of the secondary
2.) diode is a 1N0047 or something, it can handle the voltage
3.) tried other diodes

>> No.253487

>>253483
only other thing I can think of is high current could have blown the diodes if there's no current limiting resister . A capacitor is a short when completely discharged

>> No.253508

>>253477
Simplicity isn't merely measured by number of components.

But yeah, i would check those diodes and see if they're working. BJTs might have a shitty low current limit from base to emitter.

>> No.253509

What BJTs are you using?

>> No.253576

>>253487
If the voltage across the diode = secondary voltage, Diode=blown

>> No.253598

>>253435
What is the oscillation frequency of your inverter circuit? You might want to try using a Schottky rectifier diode instead of a garden-variety 1N400x diode, they have a higher switching speed. And, as someone else suggested, put a current-limiting resistor between your rectifier and the storage capacitor you're charging so you don't drag the whole circuit down when the cap is discharged.

>> No.253600

>>253576
Also, if voltage drop across the diode == ~zero, diode == blown; they tend to short out rather than open when you overload them.

>> No.253692

OP the b and c of your diodes wont work like that. Collect current for one cant be bias for the other like that. think ull find that the primary wont be recieving any current. U should half wave rectify it with ur 2 diodes

>> No.253699

>>253692
Hmm, didn't look too closely at OP's pic the first time around. Now that I do, it looks like the second transistor really should have a resistor between base and emitter to help it stop conducting when the first transistor stops conducting.