Obsolete or NOT

Discussion in 'General Electronics Chat' started by R!f@@, Mar 5, 2010.

  1. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009

    I have plenty of these leftovers. :(
    Can't use without a spec. have tried for years but I just can't seem to get the data for this whatever it is. :mad:
    Can any one tell me the specs of this thing
  2. Wendy


    Mar 24, 2008
    I can't tell from the picture, is it a diode? A view further away next to a ruler would help.
  3. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
    Last edited: Mar 5, 2010
  4. jpanhalt

    AAC Fanatic!

    Jan 18, 2008
    Googled it. No datasheet, but there are a few references to it being a power NPN transistor.
    The number I searched on was PK0(zero)30S.
  5. kkazem

    Active Member

    Jul 23, 2009
    This is an ST Microsystems part (website: www.st.com), but I can tell you that it is almost certainly a house-marked part and will not show-up on STS's website as I did many searches on it. Neither will it show-up on Google, except for other people asking the same question you are about this part.
    But all is not lost. Especially since you say you have a lot of these, you can fairly easily determine what it is. First, using a DVM with a diode checker & an ohmmeter scale, set the DVM to the lowest Ohms scale (usually 200 Ohms max) and on a piece of paper, draw a simple dwg of the part and label each of the 4 leads (the 3 at the bottom and the 1 which is the top tab). Record the Ohm reading from each lead, one-at-a-time, to every other lead, and always connect the positive DVM terminal to the first pin in the list. So you'll have, starting at whichever pin you label as pin: 1, pin1(+) to 2(-), 1(+) to 3(-), & 1(+) to 4(-). Next, Pin 2(+) to 1(-), Pin 2(+) to 3(-), & 2(+) to 4(-), etc, etc. The reason for the seemingly repeat readings like 1 to 2 and again, 2 to 1, is that a big difference in the reading with polarity will tell you something about the part. Next, repeat the process, but this time, use the diode check scale and again, check each pin to every other pin with both polarities as before. In any case where you have the resistance reading overrange or infinity, keep increasing the resistance scale slowly (to allow for settling) until you've reached the highest scale (usuallly 20 MegOhm max). Now, look at your readings. First of all, determine of the tab is connected (shorted) to the center pin or not. If not, is it connected to any other pin or not? If it is connected to the center pin, it is likely a Bipolar Junction Transistor (BJT) or a MOSFET. If it is a BJT, the diode checker should show 3 separate diode junctions. To determine if you have a diode junction, you set the DVM on the diode checker scale then, for any set of two pins, take a reading in both polarity directions. For example, pin1(+) to pin2(-) reads 0.65, & pin1(-) to pin2(+) reads open, then you have a diode junction with a low-current forward voltage drop of 0.65 VDC. If the part indeed has 3 separate diode junctions, then it is almost with certainty a BJT. If it is a BJT and the tab on top is connected to the center pin, then the center pin is almost certainly the collector. If you're lucky enough to have a DVM with a BJT gain checker, plug the pins into the DVM socket. You know which pin is the collector, so there are only 2 pins left to determine. Pick pin1=base and connect it and measure the gain. This is the forward current gain, also called beta. If you get either no reading or a very low reading, like 5 or 10, try it with the base and emitter pins reversed. If you now read a value like 80 to 200, you've figured out most of the specs. You now know what type of device it is, and have identified all of the pins, and measured the beta. The next measurement requires more equipment, to measure the primary breakdown voltage between collector to emitter (non-destructive). You either need a transistor curve tracer, or a DC power supply that goes up to at least 100 VDC (and this requires caution as voltages over about 50 VDC can be leathal). If you have such a supply, you need a high-value current-limiting resistor and a DVM. Connect the PSupply (+) to one-side of the resistor (50K to 200K Ohms, 1/4W). Connect the other side of the resistor to the BJT collector. Connect the BJT emitter to PSupply return (-). And leave the base pin open (unconnected). Place the DVM across the resistor in DC Volts mode, 200 V scale and slowly increase the DC voltage until you see a significant rise in voltage across the resistor. If you get to maximum DC voltage and get no more than a few volts across the resistor, then the device is a high-voltage BJT and you can then safely use it for circuits at least up to 100 VDC. Now, if the device is a MOSFET, then the gate terminal will initially have a reading on the DVM resistance scale (usually it will be on 20K to 20Meg scale), then the reading will quickly increase to infinity. If the tab is connected to the center pin, then the center pin is the Drain and you've identified the gate pin, leaving the only other pin as the source pin. The only question now is whether it's an N-channel or a P-Channel. Since they are by far the most common, assume it's an N-channel. Connect a lab DC power supply or a 9V battery with the (+) to one side of a resistor (100 ohm to 1K, 1/4W), and connect the other side of the resistor to the Drain pin. Connect the Source pin to PSupply or battery (-). Get another resistor, 1K to 100K, 1/8W). Connect a DVM on DC volts, 20V scale across the first resistor. Connect one-side of the 2nd resistor to the PSupply or battery (+) and momentarily connect the other side of the 2nd resistor to the gate. If you see that pretty much the entire 9V DC is read across the drain resistor, then it is an N-Channel MOSFET. Another check you can make is to momentarily short the gate to source (with the 2nd resistor removed) and the DVM should go back to reading zero or near zero. Otherwise, reconnect the device as a P-Channel by reversing the Drain and Source leads, keeping the DVM on the first resistor now going between the supply or battery (+) and the Source. Reconnect one-side of the 2nd resistor to the gate and leave the other end open for now. Momentarily connect the open-end of the 2nd resistor to the supply of battery (+). The DVM should read zero or near zero. Next, momentarily connect the open-end of the 2nd resistor to ground (supply of battery (-)), now the DVM should read close to 9V. Of course, if you're using a lab supply, this assumes you've set it to 9VDC for all of these MOSFET tests. Now, momentarily short the open-end of the 2nd resistor to plus 9V and the DVM should again read zero or near zero. If this is the case, you have a P-Channel Mosfet. You can determine the Drain to Source breakdown voltage the same way as with the bipolar detailed above. But you should first make sure that you short the source to the gate pin for that test. For an N-Channel, the high-voltage supply (+) connects thru the 50K to 200K resistor to drain with the source to ground (return); and for the P-Channel, the Source connects to there, with the Drain to ground (return). Connect the DVM across the resistor and ad slowly turn-up the DC voltage until 100 VDC. If the DVM never reads more than a few volts, then it is a high-voltage FET. Otherwise, if you get a sharp rise on the DVM at 60VDC, then it has a breakdown voltage of 60VDC, and probably has a breakdown rating of 50V or 55V DC. If the device isn't either a BJT nor a FET, If the center pin of the device has no resistance reading to the other 2 pins except infinity, then it's likely a diode, and the anode versus cathode can be easily determined with your DVM diode checker. Whichever way you connect it and get a reading like 0.35 up thru 0.7, then the pin that's connected to the DVM (+) is anode and the other is cathode. But it had better read infinity when you reverse the DVM polarity to the same two pins. If it reads from about 0.3 to 0.5, then it is likely a Shottky diode, and you can measure the breakdown the same way as with the BJT, except that the cathode goes to the resistor and the anode goes to ground (return). If it reads more like 0.6 to 0.7 on the diode checker scale, then it's probably a standard P-N junction diode. The only things that are beyond easy determination are the curernt rating of the device and if a P-N diode, the reverse recovery speed. Although if you have a scope and a square-wave generator, you could measure reverse recovery without too much difficulty. But I'll leave that for another day.
    Good luck,
    Kamran Kazem
    R!f@@ likes this.
  6. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
    Man .. I luv this guy. :pWho are you mate.
    too bad i do not have a curve tracer or a scope for that matter.
    But I had to admire you, you sure know how to explain stuff.
    I think I'll blow up a few trying to figure out what it is.:D
    By the way I PM you about the transformer secondary current?
    you did say to PM you ? But I think you are too buzy. It's OK
    I'm cool :cool:
  7. R!f@@

    Thread Starter AAC Fanatic!

    Apr 2, 2009
    Well I did Blow up one in my face just now !

    It ain't a MOSFET for sure.

    So I did a transistor switch test with DVM diode mode across CE and applied voltage as per NPN tr rule.
    The DVM indicates a forward bias at a threshold of 0.7V.

    Now I know it is a NPN power tr. Now I have to find the Hfe and it's collector rating.

    Any easy way to do this anyone?
  8. tom66

    Senior Member

    May 9, 2009
    Hfe can be measured to around 5% with a cheap multimeter with built in Hfe test.

    Collector current is more difficult. You could try saturating the transistor. At around 0.2Vce, it should be conducting the rated collector current.

    Or you could blow one up ;)
    R!f@@ likes this.