Archive for December, 2012


Image

This one has a supply current of 70 mA at 1.5V and a LED current of 25 mA at 3.3V (actually 25 millivolts measured across the 1 ohm [2 resistors] in series with the LED’s green wire).  This calculates to an efficiency of 78.6 percent.  The frequency is 250 kHz.

The circuit is almost as simple as the conventional Joule Thief; it requires a diode and 680 pF capacitor in addition to the 1k resistor.  The end of the feedback winding that was normally connected to positive is instead connected to the 1k and 680 pF as shown in the picture.  I used a SS8050 transistor, which is a Fairchild equivalent to the C8050.  It can handle up to 1.5 amp collector current.

The circuit will give more LED current for about the same supply current, or the resistor can be increased to 1.5k to give about the same LED current for less supply current.  The two current sensing resistors that are in parallel on the lower right are optional and can be removed, and the LED’s green wire connected directly to the heavy negative wire.

Advertisements

LM335Z MEASURING TEMPERATURE

Image

I decided to try another schematic for measurement of the temperature this time with LM335Z low cost sensor.

LM335Z have 0V at absolute zero temperature i.e. -273.2C and it’s output increase with 10mV/C so at room temperature the sensor will output about 2.73V

to measure this temperature with Duinomite is piece of cake:

10 SETPIN 1,1  ’setup PIN(1) as analog input

20 PRINT “ROOM TEMPERATURE IS”;PIN(1)*100-273

the problem is that PIC32 Analog input can’t take more than 3.3V on it’s ADC, so maximal temperature measured will be 57C well this still is enough for some application, but why not measure the complete temperature range -40C+100C ? (if you use LM135 the range will be -55+150C)

to do this we have to add resistor ladder which to divide the output voltage, TassyJim uses 18K/27K in his project posted at TheBackShed forum, and I found his 0.6 round divider as nice so decided to use same values.

then  I wrote this simple code:

10 SETPIN 1,1

20 PRINT “ROOM TEMPERATURE IS: “; PIN(1)*166.7-273

RUN

ROOM TEMPERATURE IS: 24.5645

it’s really not so hot in my office so I start thining what is wrong and I found it – I used 5% resistors as I had no preciese resistors so the voltage divider was not exactly 0.6 but something else and was mixing my result, no problem I took preciese ohm meter and measured R2 and R3 the values are:

R2 = 17 860 ohm

R3 = 26 600 ohm

aha so the voltage divider is 0.59829! and the coefficient I have to use in the formula is 100/0.59829 = 167.1

I corrected the formula:

20 PRINT “ROOM TEMPERATURE IS: “; PIN(1)*167.1-273

RUN

ROOM TEMPERATURE IS: 23.6145

so with not preciese resistors I got preciese result because DM-BASIC have no problems to work multiply real numbers .

ImageAs everyone knows, connecting technology in parallel has already become key technology of realizing distributed power system of high-power, but because every module characteristic of connecting the power in parallel is not totally unanimous, the module of the output with high voltage may be born and supported more, but some module may lighter by year, even empty load run, result lead to the fact share electric current many module heat stress to be loud, have reduced the working dependability of the whole power. With the development of electronic system, the requirements for power dependability, efficiency and power density are higher and higher, so it is necessary to adopt a kind of effective flowing and controlling the scheme, guarantee the output electric current of the whole power system is shared equally according to the output ability of each unit module, in this way, not only can give full play to the output ability of the power module of unit guarantee the working dependability of each unit power, but also can.

Against become main circuit for hand in and frank – hand in voltage type, it commutates sides to be controllable type as single-phase diode. This way not only controls simply but also have a higher power factor systematically. In order to reduce the device volume, reduce the harmonic wave, improve electric current wave form quality. The power component adopts module PM20CSJ060 of the third generation of intellectual power of Mitsubishi Electric Company of the high switch frequency against turning into. Module this unify encapsulation for six, inside the intersection of three-phase and bridge the intersection of circuit and structure, inside integrate at a high speed low the intersection of IGBT and chip of consumption and drive, protect the circuit. In addition, this module also integrates overheatedly and owes and presses and locks and protects the circuit, make the dependability of the system further improved . Space of six routes vector signal SVPWM that LF2407 chip outputs on the control circuit is realized that isolates IPM to drive by the photosensitive resister 6N136, and then commutate the direct current after straining the wave and press and go against to turn into necessary high-frequency alternating current and drive the compressor of air conditioner of permanent magnetism.

There is electric current that measures the circuit in the system, adopt the sensor of Hall’s electric current to measure the magneto A, C two phase forever, utilize, sample resistance and then and many stages transport show, deal with for simulation voltage signal that change among 0- 5V the intersection of electric current and signal, the pin links with integrating outside A/D converter in LF2407. Because of not having initial position where position sensor technology can’t know the rotor, the magneto works under having position sensor state after only starting too forever, so realize the detection of the initial position of the rotor with the photoelectricity type rotation encoder. Realization comes by the incident managing device of LF2407 in other protection circuit, once break down systematically, the break procedure solidifying in slice exports cutting off systematic SVPWM automatically, until the trouble disappears and resets systematically.

This text foundation permanent magnetism synchronous motor vector controls the requirements of principle and frequency conversion air conditioner, have developed a set of brand-new frequency conversion air conditioner control systems based on DSP. SVPWM control signal produced with six PWM complete comparators of LF2407 can realize that control the frequency conversion of the synchronous motor of permanent magnetism. This air conditioner of control systems have fully utilized superstrong real-time computing capability and some integrated devices of LF2407, make the whole system simple in construction, products development period is short, highly reliable.

Image

I had hoped to drop from using 40 watt incandescent to 2 watt LED bulbs.

That would be a saving of 228 watts in one chandelier and throughout our house the swap would have a total savings of 570 watts. Not a bad idea but the one we bought to test died in less than 2 weeks. It might have only been one week even.

I thought it would be fun to dissect it and see how it failed and maybe how it worked.

What better way to dissect electronics than with a hammer. “I got me’amer” – Photonic Induction.

It hammered apart quite nicely without any damage to the innards.

The pyramid was just a pack for 28 LED’s tightly packed using insulated standoff tubes. I was not sure at first if all the LED’s were in series or if there was some paralleling going on so the voltage could be lower to drive the LED’s.

It was not a complicated circuit. Some filter caps, two resistors, a diode and a SMD bridge rectifier.

Image

Holly crawdads! It still works? I’m thinking the shrink wrap around the PCB was a bit small and it had managed to short the case to the wire feeding the LED’s. I also noticed one leg of the MB6S bridge rectifier IC was not soldered down and it had almost zero copper under the leg so that could have been causing an intermittent as well.

The Fluke says the PCB is putting out ~81V DC.

The AC ripper riding at the 81V DC offset was quite pronounced at 26V PP. But the LED’s didn’t seem to mind and the human eye couldn’t pickup any 120 Hz flashing if it was causing a problem.

The LED’s themselves draw 9.45mA. Not bad for 40 watts of equivalent incandescent lighting output.

I set my power supply to series mode to output my max at 63v DC. That wasn’t enough DC directly across the 28 LED’s to turn them all on so without any further circuit tracing I can tell the LED’s are in series being each white LED needs over 2v to be forward biased.

I must have been real close to turning the pack on with 63v DC because when I jumper across a couple less LED’s the rest of the LED’s came on. A little more probing with the 63v DC source went too far and “I popped’it” – Photonic Induction again 🙂 I sure wish Photonic Induction wouldn’t have pulled off of YouTube. I loved that YouTube channel. The blackened LED’s are the ones I popped with too much voltage. It was fun while it lasted.

Image

Electronic Circuit Diagram TV vertical Using LA7841, LA7840

Image

Electronic Circuit Diagram TV vertical Using LA7841, LA7840 Basic Electronic Circuits – Datasheets

Image

Electronic Circuit Diagram TV vertical Using LA7841, LA7840

Image
The LM158 series consists of two independent, high gain,internally frequency compensated operational amplifiers which were designed specifically to operate from a single power supply over a wide range of voltages. Operation from split power supplies is also possible and the low power supply current drain is independent of the magnitude of the
power supply voltage.

Application areas include transducer amplifiers, dc gain blocks and all the conventional op amp circuits which now can be more easily implemented in single power supply systems. For example, the LM158 series can be directly operated off of the standard +5V power supply voltage which is used in digital systems and will easily provide the required
interface electronics without requiring the additional ±15V power supplies.

The LM358 and LM2904 are available in a chip sized package (8-Bump micro SMD) using National’s micro SMD package technology.

L6562 Description

Image

The L6562 is designed as one kind of two-phase current mode, PWM control IC together with companion gate drivers. This device can be used in low output voltage, high current DC/DC converters, Intel® tualatin processor voltage regulator and VRM8.5 modules.

Features of the L6562 are:(1)two-phase power conversion;(2)precision channel current sharing;(3)precision CORE voltage regulation:±0.8% accuracy;(4)microprocessor voltage identification input:5-bit VID input, 1.050V to 1.825V in 25mV steps, programmable “droop” voltage;(5)fast transient recovery time;(6)over current protection;(7)high ripple frequency, (channel frequency times number of channels):100kHz to 2MHz.

The absolute maximum ratings of the L6562 can be summarized as:(1)supply voltage (Vcc):-0.3V to 15V;(2)CS+. CS-:-0.3V to Vcc+0.3V;(3)PWRGD:-0.3V to Vcc;(4)all other inputs and outputs:-0.3V to 5V;(5)ESD rating human body model (per MIL-STD-883 method 3015.7):TBD;(6)ESD rating machine model (per EIAJ ED-4701 method C-111):TBD;(7)maximum lead temperature (soldering 10s) (SOIC-lead tips only):300℃;(8)maximum storage temperature range:-65℃ to 150℃.

 ImageSSM2164 VCF AND MODULAR WORKSTATION

1. GATE INPUT–> THIS REQUIRES A 0-5V RANGE GATE SIGNAL,

THESE ARE FROM SEQUENCERS, OR MIDI-2-CV CONVERTERS.
2. ENV OUT–> THIS IS THE ANALOG ENVELOPE AR OUT. YOU

HAVE TO PATCH THIS TO CV IN OR FM IN TO MODULATE THE

FILTER WITH THIS. YOU CAN ALSO MODULATE YOUR EXTERNAL

GEAR WITH THIS. IT IS BASED ON -/+5V RANGE. SO IT IS

SAFE TO PATCH TO YOUR GEAR.
3.AIN(1) AND AIN(2) ARE AUDIO INPUTS. SOUND GOES FIRST

TO THE PRE-AMP(BOOSTER) THEN TO THE AIN LVL KNOB.
4.CV IN–>THIS IS A CONTROL VOLTAGE INPUT. PLUG AN

ANALOG LFO, AR ENV, VCO SIGNAL ETC.
5.FM IN–> THIS IS THE SAME AS THE CV IN BUT THIS IS BI

-POLAR GIVING YOU +/- SWEEP. CENTER IS ZERO VALUE.
6. EXTREME FM–> THIS IS SO THAT YOU CAN USE “LINE

LEVEL” SIGNALS TO MODULATE THE FILTER OR YOUR OTHER

ANALOG GEAR. THIS IS JUST A DIRECT OUT COMING FROM AIN

(1) BOOSTER(1). SO WHAT YOU DO IS PLUG IN YOUR FAVORITE

DRUM MACHINE OR VIRTUAL ANALOG IN AIN(1), TURN UP THE

BOOSTER TO AMPLIFY BUT HAVE AIN(LVL)1 AT ZERO SO YOU

DON’T HEAR IT. NOW PATCH FROM EXTREME FM OUT TO CV OR FM

INPUT. TURN THE FILTER ALL YOU WILL HEAR IT MODULATE TO

YOUR EXTERNAL LINE LEVEL SOURCE.
7. FILTER OUT–>THE IS THE UNBALANCED SIGNAL THAT GOES

TO YOUR MIXER OR AMP.
8. LFO OUT–>THE IS THE LFO OUTPUT. IT IS A SLOW

OSCILLATOR SO YOU CAN PATCH IT TO AN AIN TO HEAR IT IF

YOU WANTED TO MAKE A PORTABLE SOUND BOX.

BY ALL MEANS TURN UP THE REZ TO SELF-OSCILLATE AND GET A

CLEAN SINE WAVE. THIS IS ONE OF THE BEST ONES I HAVE

embedded systems project

Image

I’m going to build an USB device on STM32 which can communicate (both ways, using wireless RFM70 2.4GHz transceiver module) with other devices, built on AVR μC (probably ATMega8).

I’ve gathered some stuff:

5x RFM70 2.4GHz transceivers – they are cheap, range 60m (open air) is fine for me
STM32 Value Line Discovery – as a cheap ST-LINK programmer/debugger (much cheaper than normal P/D devices…)
STM32 (STM32F103C8T6) – as a target STM32 – on AVT kit, with RTC quartz, goldpins and SWD interface
ATMega8 (from previous project) and ATMega8 Low Voltage (to work with 3.6V battery)
4x 3.6V batteries – taken from some similar-purpose devices I’ve got from my father
loads of resistors, capacitors, LEDs, cables and other stuff…

These are the most important things I need.

I still don’t have a name for the project, it’s hard to talk about it with someone.

Today I’ve finally managed to set up Discovery Board and STM32 on AVT kit, connect them and debug a simple LED-blinking program. I will write about it, probably tomorrow because it was a real pain in the ass so I think it would be useful for future generations.

TDA7000 FM Receiver / TV Tuner

Image

This simple one chip FM receiver / TV tuner will allow you to receive frequencies from 70 up to 120MHz. With this small receiver it is possible to pickup TV stations, entire 88 – 108MHz FM band, aircraft conversation and many other private transmissions. It is a perfect companion to any FM Transmitter especially if FM band in your area is very crowded. TDA7000 receiver offers very good sensitivity therefore it will even allow you to pickup weaker signals that cannot be heard on conventional FM receivers.

A neat feature of presented TDA7000 FM receiver is a voltage controlled oscillator similar to TV tuners that are used in television sets. Frequency is tuned by varying the input voltage to the oscillator. The advantage of this type of oscillator is that you can use regular 100K potentiometer to precisely tune to a given broadcast. Tuning can be performed much quicker and precisely than by using a trimmer (variable capacitor). Trimmers will also shift the frequency as you touch them where potentiometer will not. Trimmer also needs to be placed on receiver’s PCB to minimize the stray capacitance where potentiometer can be conveniently placed anywhere you want because it will not be affected by any external capacitance.