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[Moved]: Reading schematic values

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FootTea

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I saw a schematic diagram of a power supply and it doesn't seem to use a unit for its capacitance. I can only see 0.01/2K. Is it right if I consider it as 10nF? Any standarda on this? What does this /2K mean? I also saw resistor values 10/3, 47K/1 18K/3. What does this slash mean? Thanks.
 

Re: Reading schematic values

Hi,

I´d say it is no standard.
What the values mean often is only obvious by looking at the circuit itself, therefore you should upload it.

Klaus
 

Re: Reading schematic values

Hi,

now its more obvious.

All capacitance I see are in uF
The /2k after the capacitor value is the voltage. You see "CY" is a special safety cpacitor. Also C12 should be a "Y" class safety capacitor.

all resistors in Ohms.
The /1 after a resitor value most probably is the power dissipation in W, but imaybe it is a random "size" description.
Here R12 should be rated for high mains voltage. A 0603 chip resistor for example won´t do the job.

The schematic is not very consequent in giving these values. Sometimes they exist, sometimes not.

A doubtful R10, P3 combination.
Missing voltage of C5, C6...
and so on.

Klaus
 

Re: Reading schematic values

It really feels like uF.

I will be calculating my own components when I get home. Trying to ask first to hasten the progress while on mobile phone.

I will check on capacitor classifications. I haven't gone on these technicalities before. So with the slashes on the resistors. I was trying to find a pattern too. I thought it has another noncoventional way of writing resistor and capacitor values.

It is logical that they will be inconsistent on labels and values since they are selling the schematic. I would have downloaded it right away and not pay.
 

Re: Reading schematic values

A curious schematic nevertheless. It looks like the supply to the IR2153 is crowbar protected from the core voltage of the transformer rather than a winding on it.

Brian.
 

Re: Reading schematic values

The pvm 400delux I see is rated 1 kv to 15 kv. Looks like there used for plasma generators I believe.
 

Re: Reading schematic values

betwixt said:
A curious schematic nevertheless. It looks like the supply to the IR2153 is crowbar protected from the core voltage of the transformer rather than a winding on it.

Brian.
Click to expand...

I've heard of crowbar before but didn't know this was it. (Still a suspicious parallel potentiometer though.)
 

Re: Reading schematic values

Kajunbee said:
The pvm 400delux I see is rated 1 kv to 15 kv. Looks like there used for plasma generators I believe.
Click to expand...

Definitely. :) I'm planning to use the 90mA transformer and a doubler at the load side to reach 35kV operating voltage.
 

Re: Reading schematic values

It looks like the supply to the IR2153 is crowbar protected from the core voltage of the transformer rather than a winding on it.
Click to expand...

Voltage on the core when there is a ground in the core?
 

Well, it capacitively couples some pick-up from the core to a rectifier to produce a DC voltage. A proportion of that is taken by the potentiometer to the gate of the SCR. If the SCR gate rises above trigger voltage, it turns on and dumps the IR2153 supply voltage to ground causing it to reset.

The puzzle it, why use pick-up from the core, presumably as a protection mechanism but it would be very unpredictable. Maybe the symbol is incorrectly drawn and it is some kind of field probe NEAR the discharge point and not the transformer itself.

Brian.
 

Phew, I thought I was the only one confused. I will recheck when I get home.
 

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