Latest threads in Hobby Electronics Basicsshow only best voted threads
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what is the symbol for a solenoid
such as thanks
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15 years ago
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Simple emitter followers
I'm reading this (fascinating reading): and I noticed the capacitor. What value is this, typically? Should it be electrolytic, ceramic, ??? I also noticed one end is black, and the other white. Is the...
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15 years ago
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Paralleling FETS
I'm thinking of using a dual mosfet in a SC-88 package (NTJD4401N), in a current source. The FET's will be controlled by an LMV611 opamp. They don't state in the datasheet how well matched the pair is...
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15 years ago
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OpAmp differential voltage range ?
I thought I found an ideal micro power OpAmp for another low power LDO I'm building in the LMV641. Small offset, RR output, 10MHz GBW, 2.6 V/us and still pretty good drive capability +/- 20mA. There's...
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15 years ago
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1500 W electric heater control
I've got a 110V, 1500 W immersion heater (similar to the kind used in electric water heaters). I'd like to control it a little more precisely than simply switching it on/off every 30 seconds. Is this...
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15 years ago
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RCD tester
Can someone just confirm my sums?? I want to put a resistor inside a plug to test the 30mA RCD. I reckon I need a 8k 10w resistor. R = 240/0.03 = 8000 ohms. W = 0.03 x 240 = 7.2W. 8.2Kohms or 6.8kohms...
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15 years ago
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AXION TV
I don't know if I am asking in the proper group.... but I have an Axion LCD 8 inch flat screen TV with a card reader. It is a stand alone TV. I only use it for watching TV. What it is.... is that I...
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15 years ago
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Junkbox DC-DC Converter
I worked up the circuit below to create an isolated DC supply, and it works (sort of). It's a 555 astable running at ~500KHz into a voltage doubler. I get an unloaded voltage of 7v, dropping to 1.5v...
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15 years ago
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class A amplifier
Hello, First, I must say that I have not done analog electronics since a long time. So please be indulgent ! I want to do a small class-A music amplifier + preamp. I want to find the best trade-off...
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15 years ago
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Simulating dependent sources
I'm writing a circuit simulation program as an exercise and I'm using the nodal method. The nodal method requires every branch current to be a function of some branch voltage so the circuit can be...
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15 years ago
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Simple voltage question
I'm trying to get a steady 5 volts from a 6 volt battery. The 5v will power a circuit that draws a variable amount of current (between 70 and 100 ma). I've used LM7805 in the past but I know they need...
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15 years ago
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who knows about noises?
hi every body I have a signal generator thak works with 555 sometimes I see a a noise like digital FM that I think it from 50hz 220 (network voltage) what i can do to remove it I dont know even when...
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15 years ago
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Latchup? RS-485 receivers
I have a project where the input of an RS-485 receiver can have voltage on it before the main power supply comes on. My project has worked well in the past when my cable's bus voltage was 12v and I...
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15 years ago
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TV with short circuit - how do I find the short?
A friend of mine gave me an old 27 inch TV that no longer works. Upon inspection of the insides, I noticed the "5A 125V GMA" fuse was blown. I purchased a 10 pack of these fuses, and when I replaced...
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15 years ago
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Switch Question
I haven't done any electronics in years so please excuse the simple question. Google made me confused. A device has two three-wire ribbon cables. I want to put an On-Off-On two-position switch on the...
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15 years ago
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