Tag Archive: IC


Image
 Among the final amplifier we called. Regional Power Amp, will it work on several well-known as Class A, Class B, Class AB etc. Each class of the above, to honor the Class A was superior to the sound quality. best. However, class A power output to a low of 20 percent compared with a loss of power or the power consumption of about 5 times the power output. Therefore, the problem of heat Although it has not paid any audio. But anyway, despite the low-watt power, it also provides crystal clear sound quality than Class B and Class AB.

      Principles of integrated amplifier class A is IC1 – NE5532 to extend signal input through the C1 to increase 15-fold. The signal output from the pin 1, signal hemisphere positive through C2 to access Q1-BD139 and Q3-2N3055. is powered by Darling ton, amplifiers and signal the intensification of the negative side of C3 through the amplifier with the Q2-BD140 and Q4-MJ2955. This is the Darling ton, too.

Then the output signal from the positive side of the pin E of the Q3 and the negative side of the pin out of the E in Q4 through R10 and R11, to prevent short circuits and then output to the speakers. This will power up to 5 watts. The D1-D4 acts as a rectifier in the DC bias for Q1 and Q2. And VR1 is adjusted to a constant current bias is at work. The Q1-Q4 will be attached sheet cooled, Q3 and Q4, especially the thermal plate must be large. Because the circuit has high energy loss.

My H-Bridge consume 3ma@3.3v when there is no load and both inputs are zero,

    How can i reduce it ?
    my goal is <100uA
Image
Q2 and Q8 are SS8550 and Q3 and Q9 are SS8050, other Qs are 2N2222A

Image

  The following CD4017 circuits have not been tested and is presented here as a possibility only. If you experiment with this circuit, please send me any problems found so that the circuit can be updated.

  The following circuits are designed to change the duration of each positive output pulse from the astable timer. The circuits use a CD4017 Decade Counter / Decoder to provide nine or ten steps in the cycle.

  The first circuit operates with a repeating ten step cycle. Each output pulse is longer than the previous until a count of ten is reached at which time the cycle will repeat.

  The second circuit has a nine step cycle that stops at the end of the cycle. The cycle is restarted or reset when the RESET input is briefly made high.

  The CD4017 can be configured to give count lengths between 1 and 10. Refer to the timing diagram in the CD4017 data sheet for a better understanding of the IC’s operation.

I know how to build a big digit but how the heck did you control that much current with such few ICs and such few control lines? Ahh, I’m glad you asked. Here are some fun pointers about how to control large numbers of seven segments LEDs.

Now if you’re not a hardware person, get ready for some technical jargon.

A PIC 16F877A has quite a few I/O pins (around 32). But if you start doing the math, you see just how limited we are.

6 digits * 7 segments = 42 channels

Sure, we could find a microcontroller that has 42 available I/O pins, but there’s got to be a better way! This is actually an age-old problem. Turns out there are chips out there! The 74HC4511 is the magical chip that takes a Binary-Coded-Decimal (BCD) input and outputs the correct pins to create that binary number on a seven-segment display.

Okay, so we go from seven lines down to four, big deal? There is a latch on the 74HC4511. This latch allows us to share the 4-bit bus with all the channels, and then just toggle the latch pin on the digit we need to talk to. Maybe a schematic will help:

Image

You can see four Control lines. This is the BCD bus. There is also six Driver lines. These Driver lines activate the latch on each ‘channel’.
Image

U6 is the 74HC4511. U7 is a ULN2003A. JP1 is the RJ45 jack. Just stick with me a bit longer!

The ULN2003A is a high-current Darlington array. Darling what? This IC has seven channels. Each channel can control up to 500mA. When 1B goes high, current is allowed from the ‘1C’ input to ground.

So when the Num1_f pin goes high, current flows from RAW, through the LED Light Bars in the big digit, into 1C, and then out through GND. This may seem a little bit odd at first. Maybe this will help:
Image

Okay so now for the chain of events.

The PIC parses out the GPS time from NMEA sentences coming out of the Lassen iQ receiver at 4800bps.
The PIC decides that the time is 6:45:33, so a ‘3’ needs to be displayed on channel 1.
A binary three (0b.0011) is put onto the bus.
Driver1 is pulled low, then driven high. Because all other driver lines are kept high, the other drivers ignore this bus data.
The 74HC4511 for channel 1 sees this binary number, notices that it’s been latched, and then outputs the correct segments to light up a three. Segments A, B, C, D, and G go high.
The ULN2003A detects these lines (Num1_a, b, c, d and g), goes high and allows current to sink through 3C, 4C, 5C, 6C, and 2C.
The LED Light Bars inside the digit (located farthest to the right) light up the correct bars to display a three.

It’s really pretty slick. The system is completely scalable. To add another seven-segment display requires only one additional I/O pin for another DriverX line. The PIC 16F877A could control as many as 28 digits. Have you ever seen 28 digits next to each other? How about 18″ wide and on a wall? That’s really huge.
Image24

That’s it! Sorry the tutorial ended up being so long. This project took about two weeks of cutting and figuring out how to best create the digits. The firmware took about an hour and hardware layout took about three (we’ve used most of the basic components before). Let us know what you think.

HI, I’m working on a circuit that uses two 555 timers. At the electronics store, they gave me a handful of 555 chips, I only noticed the difference when I finished my circuit: the R1 value is shorted out, my R2 value is 150 Ohms, and the electrolytic cap is 10 uF. (see the schematic with R3, D1 and D2 replaced with a single piezo speaker).

ImageThe thing is, if I put in the 555 chip marked LM555CN, it appears to be ‘always on’. But, if I use the Texas Instruments chip marked NE555P, the circuit works as expected, that is, it generates an annoying screech on a piezo speaker. What is the difference between these two seemingly identical chips? Is it a quirk in the TI chip that it works when R1 is just shorted out? And lastly, is there a way around this problem other than me sitting at the electronics store picking out the TI chips?

Also note – the piezo speaker doesn’t have any oscillator in it, that is, when you apply raw power to it, it just clicks once and sits there, that’s why I have the second 555 timer, and it’s not an option to change out the speakers at this point.

MAX232CSE line driver/receiver

Image
The MAX232CSE line driver/receiver is intended for all EIA/TIA-232E and V28/V24 communications interfaces, particularly applications where ±12V is not available. These parts are especially useful in battery-powered systems, since their low-power shutdown mode reduces power dissipation to less than 5μW. The MAX232CSE uses no external components and are recommended for applications where printed circuit board space is critical.
 
MAX232CSE absolute maximum ratings: (1)Supply Voltage (VCC): -0.3V to +6V; (2)V+: (VCC – 0.3V) to +14V; (3)V: +0.3V to +14V; (4)Input Voltages; (5)TIN: -0.3V to (VCC – 0.3V); (6)RIN (Except MAX220): ±30V; (7)RIN (MAX220): ±25V; (8)TOUT (Except MAX220): ±15V; (9)TOUT (MAX220): ±13.2V; (10)Output Voltages; (11)TOUT: ±15V; (12)ROUT: -0.3V to (VCC + 0.3V); (13)Driver/Receiver Output Short Circuited to GND: Continuous; (14)Storage Temperature Range: -65℃ to +160℃; (15)Lead Temperature (soldering, 10s): +300℃.
 
MAX232CSE features: (1)For Low-Voltage, Integrated ESD Applications MAX3222E/MAX3232E/MAX3237E/MAX3241E/MAX3246E: +3.0V to +5.5V, Low-Power, Up to 1Mbps, True RS-232 Transceivers Using Four 0.1μF External Capacitors; (2)For Low-Cost Applications MAX221E: ±15kV ESD-Protected, +5V, 1μA, Single RS-232 Transceiver with AutoShutdown.

This is one application circuit of LM324N,If you need more circuits,please download LM324N’s pdf datasheet.

Image

 Image
An ATmega64 is used for the controller. The MCU has an external memory interface, it benefits the applications that require a certain memory. The waveform data is loaded from a memory card and stored it to the wavetable located in the 256 Kbit external memory. The wavetable, 16 bit word, 8192 samples and two channels, fits to the entire memory. The system clock is supplied from DAC. The frequency exceeds maximun allowable working frequency of the MCU, however it works with no problem.

Image
Microlab ATX 400w KA7500 Power supply micro lab 400watt atx ka7500 lm339 2sc2625 st3040 st1020 sbl2040 microlab atx 400w 2sc5027 fr107 2sc5344y atx tamir şema atx smps circuit, atx smps repair schema.

Image

Normally begin to learn about electronics power supply from the battery, for example, 9 volts, 1.5 volts, 6 volts etc. But there are disadvantage that when using battery power is discharged. I need to buy a new one. Consume more.
We should the dc power supply have a choice of AC voltage. Which it must provide a output voltage as usage often is 1.5volt, 3 volts, 4.5 volts, 6v, 9v, and the current is about 1 A.
When we view many circuit ideas, found that the as figure this below (number second the power supply projects in my life) have the best fit. We use a dc voltage regulator number LM317T is the heart of the circuit. Featured, is the constant voltage. Low noise. Almost equal to the voltage of the battery. And short-circuit protection as well.
How it works
When we push power switch (S1) on, the AC-line voltage will pass through a fuse F1 and come to transformer T1 to reduce AC volts down to 12 volts
– Then this current flow through the bridge diode model (D1-D4)-1N4001 to full wave rectifire as DC current and through C1 to filter current to smooth up and has C2 filter ripple signal before into LM317.
-LED to display power on the circuit, with R1(2K) currents to reduce it.

Image

LM317 Linear power supply Regulator selector 1.5V,3V,4.5V,5V,6V,9V 1.5A

– The output voltage is determined by rotating a selector switch S2 a level voltage 1.5,3,4.5,5,6,9 volts respectively.
– C5 (10uF) control impedance and reduce a transient at output of IC1

– C3 (10uF)- help to reduce the ripple before is amplified when the output voltage rise up.
– C4 (0.1uF) reduce the ripple at output.
– D5 and D6(1N4001) for protects IC1 from discharging of C3 and C5 respectively. In case the input of IC1 is shorted.
The maximum output current about 1.5A depends on size of the transformer We sould choose size of 2A., Or size 1A for those who want to 1A output current only.