| T O P I C R E V I E W |
| skywriter |
Posted - Nov 19 2009 : 01:08:16 AM
http://www.aaroncake.net/Circuits/12VDC_To_24VDC_Converter_Circuit.asp
It seems the circuit above is wrong. Q1 would never open because there is no difference of potentials between base and emitter.
Who ever tried to make it? I tried but it seems nothing to do but send 607 Hz to Q1's base. |
| 9 L A T E S T R E P L I E S (Newest First) |
| baqabaqa |
Posted - Dec 07 2009 : 12:50:44 PM
if this circuit is true , what frequency will appear out ? |
| skywriter |
Posted - Dec 07 2009 : 09:24:51 AM
Measuring of L can be done very simple! I connect the coil parallel to capacitor of the known value. Then i connect first end of the capacitor to the output of the soundcard and the second end to the mic input. The schematics looks like this:
C
out(sig) ---||--- mic(sig)
out(gnd) -------- mic(gnd)
Then i use baudline software (see above) to generate gauss noise. Then find resonance frequency using gain-frequency characteristic.
L can be easily calculated from resonance condition. As we know the equation of resonance looks like this:
wL=1/(wC)
where w=2*Pi*N
where N is resonance frequency (Hz). |
| Aaron Cake |
Posted - Dec 01 2009 : 09:18:28 AM
I'm not sure how one would measure that, or if it is even easily possible. Best bet is to look up the specs of a toroid of approximately the same construction and make a guess.  |
| skywriter |
Posted - Dec 01 2009 : 02:20:58 AM
I followed links you show. Good theory but the question still: how do i know the value of permability of the core?
Because i don't know the value of unknown core so i decided that it will be simplier and moe reliable just to measure it using LC resonance effect. |
| Aaron Cake |
Posted - Nov 28 2009 : 11:32:58 AM
I don't know the inductance of L1 as I have never run the calculations and it was not specified in the circuit. If you find a toroid of similar dimensions and wind it as shown, then the circuit will work.
http://hyperphysics.phy-astr.gsu.edu/Hbase/magnetic/indtor.html
http://www.66pacific.com/calculators/toroid_calc.aspx |
| skywriter |
Posted - Nov 22 2009 : 07:33:09 AM
Yes, i can get some toroids. But you didn't specified the exact inductance of L1 so i can't make my one.
I think it is bad way to look for toroid of the same size and the same permeability as yours one and wire of the same diameter as yours.
Instead i prefer made or buy coil of the certain inductance which can be measured using sound card and this beatyful software: http://www.baudline.com/solutions/swept_sine_vs_wgn/index.html .
Can you inform us about the inductance of L1? This can be simply made by connecting capacity parallel to coil and measuring resonance frequency. |
| Aaron Cake |
Posted - Nov 21 2009 : 11:02:41 AM
Wow, I can't believe I made such an elementary mistake while drawing the diagram. I'll update the schematic with the missing ground.
The coil you have used looks to be either air core or have a small ferrite core? You really need a better core for this. Toroids are easily salvaged from computer power supplies. |
| skywriter |
Posted - Nov 19 2009 : 11:48:41 AM
I connected Q1's emitter to ground. Now the circuit gives 26 V on output but under 120 Ohm load it downs to 11.5V.
Under this load circuit consumes 600 mA from 12.2 V battery.
I don't want to make exact copy of author's toroidal coil because it is difficult for me to find appropriate core.
So instead of author's coil i use factory-made coil http://electronica.bashel.ru/info/1201/RCH.jpg with L=1 mH (not 1 mkH) and R=1.8 Ohm.
Is it possible to tune circuit for predefined coil? |
| audioguru |
Posted - Nov 19 2009 : 08:48:59 AM
I think the emitter of Q1 and the parts connected to it are supposed to connect to ground. |
