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    PCB Transfers

    Hi All, I'm looking for a cheap and easy way to transfer my circuit onto copper board. I'm using a piece of software that can print the tracks 1:1 on a printer. I'm aware of the various methods out there, photoboard+UV light, transfers, laser printer/toner method, etch-pen, etc. I came across a...
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    Phototransistor Information

    Hi audioguru, I've checked the datasheet for the LM311 and according to the Electrical Characteristics table the response time is 200nS given a 100mV input step and 5mV overdrive(?) which appears to be the very much the same as the LM6511 which has a 180nS response time with a 100mV input step...
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    Phototransistor Information

    Hi, Will this circuit work ( see attached )? I've determined that the worst case scenario is that a 1uS flash of light needs to be detected with a 66us delay before the next flash. Once I get this last problem nailed down I can build my board! SFH2030F.pdf
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    Phototransistor Information

    Great! There's the SFH2030 that has a rise/fall time of 5nS! Currently the phototransistor in my circuit is supplied with 5V and acts as an input to a LM311N comparator. Can I use the photodiode as a drop-in replacement for the phototransistor or will there be issues I need to address? Thanks...
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    Phototransistor Information

    Hi, I'm using a phototransistor ( SFH300-3 ) in my circuit that has rise/fall times of around 10uS. I need a phototransistor that will respond to 2uS or quicker pulses of light. When the manufacturer specifies a rise time for example, does this mean that the phototransistor has to be illuminated...
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    Cross

    Couldn't you use a comparator that takes both inputs. When the output is zero, the signals are at the same voltage, i.e. 'crossed', then all you have to do is to take a reading from one of the inputs for the actual value.
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    LM2917N F-V converter IC

    Hi, If you can determine what values for R1/C1/C2 I need to solve the problem please let me know! :D Will the cmos inverters just invert the signal? If this is the case then it won't solve the problem as a
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    LM2917N F-V converter IC

    Hi, I think I've found the problem! :D There's a formula in the datasheet for determining the maximum frequency that can be input: Fmax=I2/C1*Vcc=0.00018/(0.0000000047*7.57)=5060Hz. At this frequency, the half cycle pulse width would be 0.098ms which from my testing turns out to be just about...
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    LM2917N F-V converter IC

    Hi audioguru! I remember you helping me out on my comparator problem!
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    LM2917N F-V converter IC

    Hi All, I've almost finished my project for a tachometer circuit. Testing went well until I appear to have hit upon a snag for which I need some help. It concerns the LM2917N frequency to voltage converter IC, which I can happily 'program' to give the correct output with a given frequency input...
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    Comparator usage.. Help!

    Spot on!
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    Comparator usage.. Help!

    Hi Again! ;D Following on from the problem with the comparator ( which is now solved, thanks! ), I've since progressed with my circuit and have managed to get things more or less working. This sub-circuit is ultimately to act as a light detector ( using a laser diode as the light source ) to...
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    Comparator usage.. Help!

    Hi All, Well after all that, it turns out that the 1K pot I'd replaced the 1M pot was in fact also a 1M pot... doh..!!
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    Comparator usage.. Help!

    Hi, I've attached a schematic ( I hope! ). I've changed the 1M pot to a 1K pot. Results are exactly the same as the previous tabulated results. Cheers, Salvatore.
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    Comparator usage.. Help!

    Hi, To keep things simple, I've reduced the circuit to not include hysteresis. I can't seem to find how to attach a schematic (sorry!), but the circuit is literally the LM393, +5V supply to the comparator and two pots, one 1Mohm for the -ve reference input and a 10K for the +ve input, all...
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    Comparator usage.. Help!

    Hi All, I've got a small project on the go and need some advice. It concerns the use of voltage comparators, in particular the LM311 and LM393. I've got a breadboarded ( plywood and cup screws!! ) test setup and I've managed to get both comparators to work including some hysteresis, but I am...
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    Input to the Parallel port

    Hi, Have you made sure your parallel port is set up for data bi-directionality? The default is usually for one-way only, e.g. out to a printer. To set the port for bi-directionality you need to go into the PC's BIOS and make the change there. Hope this helps. Salvatore.
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