Hobby Electronics Basics

Reactive load impedance in a transformer (Circuits I don't understand #1)

Having a resonant circuit in the secondary of a transformer has been bother ing me for quite some time. Circuit books t...

12 comments posted 13yrs

posted by mhdpublic

12 comments posted 13yrs posted by mhdpublic

Thermal management of through-hole leds

I have some leds in 8 mm through-hole packages, rated for 0.5 W, maximum steady current 100 mA. The legs are extra wide...

4 comments posted 13yrs

posted by la

4 comments posted 13yrs posted by la

oscilloscope without wire ground

Is there any risk to use oscilloscope without wire ground? Because with wire ground there is a short circuit when I use...

33 comments posted 13yrs

posted by tobiasgadelha

33 comments posted 13yrs posted by tobiasgadelha

led's

I need help with a way to light up my SWR meter with internal led which wou ld be really close to RF passing thru the S...

97 comments posted 13yrs

posted by my2004vette

97 comments posted 13yrs posted by my2004vette

Wheatstone measurement bridge

Wheatstone measurement bridge is kind of very accurate measurement approach due differential measurement. But it is als...

0 comments posted 13yrs

posted by pchung705

0 comments posted 13yrs posted by pchung705

Need help designing a simple control system

This problem probably amounts to determining the constants of a curve. Furthermore, the "curve" is most likely a line:...

7 comments posted 13yrs

posted by ramon

7 comments posted 13yrs posted by ramon

Again! Current-limiting resistor for LEDs

The supplied voltage is 3V. The forward voltage drop over LED is 3V. What is the resistance of current-limiting resistor...

32 comments posted 13yrs

posted by toylet.toylet

32 comments posted 13yrs posted by toylet.toylet

Roomba vacuum cleaner

Just picked up my second one at a garage sale. (Total investment = $8 so far) Anyway, it would be nice if I could get o...

1 comments posted 13yrs

posted by ivanvegvary

1 comments posted 13yrs posted by ivanvegvary

Is this homemade battery charger circuit dangerous?

The other day I found plans for a $3 battery charger that was just a diode and light bulb in series with the battery, u...

41 comments posted 13yrs

posted by kanon11

41 comments posted 13yrs posted by kanon11

A capacitor/resistor question

Greetings All, In the book "Electric Motors and Control Techniques" a circuit is illustrated that is for the dynamic br...

2 comments posted 13yrs

posted by etpm

2 comments posted 13yrs posted by etpm

Bluetooth questions

I have this tiny MP3 player made by Sansa that I like a lot. Enough that I might buy a couple more to replace the one I...

2 comments posted 13yrs

posted by etpm

2 comments posted 13yrs posted by etpm

Is this preamp appropriate?

Greetings All, My car has a minijack input for the Alpine stereo. When I plug in any MP3 player the volume level is qui...

13 comments posted 13yrs

posted by etpm

13 comments posted 13yrs posted by etpm

rc timer circuit help

Hi I have a GSM controller that can switch a relay for a minimum time of 1 sec, however I need a 300ms pulse. I am look...

15 comments posted 13yrs

posted by keithbc86

15 comments posted 13yrs posted by keithbc86

Heathkit is back

Check out http://www.heathkit.com/heathkit-faq.html -- --------------------------------- --- -- - Posted with NewsLeech...

1 comments posted 13yrs

posted by Stoller

1 comments posted 13yrs posted by Stoller

Transistor as a current limiter

Hello. I need to wire some leds, and I figure that a transistor for each series is a good way to ensure that the leds g...

110 comments posted 13yrs

posted by la

110 comments posted 13yrs posted by la