Latest threads in Hobby Electronics Basicsshow only best voted threads
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Difficulty identifying SMD semis via markings
I've never had to look up a SMD semi before now. Unlike JEDEC codes, these less-than-brief alphanumeric codes have no standard that I can find. And if there's no manufacturer mark (or it has become...
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13 years ago
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15 | |
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Resistor values with a PUT
From what I have read, the gate of a PUT is what determines its threshold voltage, so you would control that with two resistors, one between positive and the gate, and the other between the gate and...
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13 years ago
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resistor value for LM317
usually a fixed resistor value of 220 ohm is used, with a 5k trimmer. Is there any problem if I use a 450 ohm resistor with a 10k trimmer? Maybe the current on the regulation pin will be too low? Any...
4
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13 years ago
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4 | |
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Subtractor circuit impervious to components tolerance?
Hi, I'm wondering if there's some circuit configuration (presumably an op-amp based design) that would subtract two signals (say, two audio signals) in a way that is *100% and absolutely unaffected*...
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13 years ago
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18 | |
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Bode ploting
I am a Portuguese science student and although I am a little ashamed to be doing this question, I really need to do it as I have a practical exame this week. One of the tasks we have to do is to make...
1
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13 years ago
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A question regarding voltage controlled oscillators
Maybe this is a stupid question, but could some electronics guru clarify this a bit ? Current voltage controlled oscillator designs, based on fixed frequency oscillators - e.g., Colpitts have a...
2
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13 years ago
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555 timer triggering
Thanks for the replys. I am using the monostable configuration that is shown in the datasheet (unsure of manufacture but I think its a universal configuration), it uses two external caps between pin 5...
2
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13 years ago
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What is the difference between a socket and a female header?
Subject says it all - I thought that a socket was female, which headers were then stuck into. But if that is the case, what is a "female" header, if not just another name for a socket? Is a female...
8
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13 years ago
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8 | |
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Triggring a 555 timer in monostable mode with a compartor output
Im trying to tigger a 555 timer with a comparator. Im using the 555 timer in a monostable configuration with the supply voltage at 7 volts. When the input to the 555 comes via the high output of the...
13
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13 years ago
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13 | |
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Pole Mount Distribution Transformer Design
Hi everyone, I'm currently trying to design a 20kVA (11kV - 230V) pole mount distribution transformer for a project. I'm having some difficulties deciding which core material and winding materials to...
7
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13 years ago
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VCC width
When I started designing PCBs, I was given an advice to route GND with 50mils and VCC with 25mils. But now I read on the net that VCC should be wide, also. I make two-layer digital boards only. If I...
20
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13 years ago
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20 | |
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Quick Test for Optocoupler needed
I need to test a Sharp PC817 Optocoupler. Can I apply a 1.5 volt AA cell to pins 1 and 2 (pin 1 the positive side)... then simply check the change in resistance with a VOM on the output side (pins 3...
4
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13 years ago
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4 | |
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PIC prgramming
I'm trying to program a PIC 16F628A using a Matrix Multimedia HP488 programmer with PPP ver 3. The PIC should be responding to an input on RA4 but it isn't. I suspect that the PIC is in low voltage...
8
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13 years ago
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How can a Philips AC-DC transform make so much noise?
Hi, I am using a Philips HQ 8000 100-240V /D 50-60 Hz, 9W, shaver charger and transformer. I always let it plugged in, and then, to charge the shaver, I plug the shaver in the charger, and...
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13 years ago
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How do GPS tracking devices work?
Specifically, how do they transmit if they are, for example, inside a shipping container? Is there a hole drilled for an antenna? Or a fiberglas patch made to replace some of the steel top or side?...
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13 years ago
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