50 watt Power Amp OTL by LM3900, 2N3055

This be power amp OTL 50Watt use IC LM3900 and 2N3055 x 3pcs transistors to pillar equipment. Follow very circuit keeps to are Class ab then have a voice good loud. When , be amp OTL you then are certain that build easy use power supply the group is one 70V sizes by must use Current low 2Amp go up. Then have a voice good another thing you will like that amplifier. This durability do not make a loudspeaker a lose easy.

LM3914          IRF3205           PT4115          2N2222A            NRF24L01

Digital voltmeter using ICL7107

The circuit given here is of a very useful and accurate digital voltmeter with LED display using the ICL7107 from Intersil. The ICL7107 is a high performance, low power, 3.5 digit analog to digital converter. The IC includes internal circuitry for seven segment decoders, display drivers, reference voltage source and a clock. The power dissipation is less than 10mW and the display stability is very high.

The working of this electronic circuit is very simple. The voltage to be measured is converted into a digital equivalent by the ADC inside the IC and then this digital equivalent is decoded to the seven segment format and then displayed. The ADC used in ICL7107 is dual slope type ADC. The process taking place inside our ADC can be stated as follows. For a fixed period of time the voltage to be measured is integrated to obtain a ramp at the output of the integrator. Then a known reference voltage of opposite polarity is applied to the input of the integrator and allowed to ramp until the output of integrator becomes zero. The time taken for the negative slope to reach zero is measured in terms of the IC’s clock cycle and it will be proportional to the voltage under measurement. In simple words, the input voltage is compared to an internal reference voltage and the result is converted in a digital format.

The resistor R2 and C1 are used to set the frequency of IC’s internal clock. Capacitor C2 neutralizes the fluctuations in the internal reference voltage and increases the stability of the display.R4 controls the range of the voltmeter. Right most three displays are connected so that they can display all digits. The left most display is so connected that it can display only “1” and “-“.The pin5(representing the dot) is connected to ground only for the third display and its position needs to be changed when you change the range of the volt meter by altering R4. (R4=1.2K gives 0-20V range, R4=12K gives 0-200V range ).
Circuit diagram.

Notes.

    Assemble the circuit on a good quality PCB.
    The circuit can be powered from a +/_5V dual supply.
    For calibration, power up the circuit and short the input terminals. Then adjust R6 so that the display reads 0V.
    The ICL7107 is a CMOS device and it is very sensitive to static electricity. So avoid touching the IC pins with your bare hands.
    The seven segment displays must by common anode type.
    I assembled this circuit few years back and it is still working fine.

pulse signal interfaces EPC1PC8

The pulse signal examined is a driving signal of the power, used in the propulsion power to support, the drive current is usually several mA to several numerous mA, adopt the open-collector gate OC The form is exported, it is usually 12 – 30 V signal. For compatible many kinds of signal levels, and can isolate power type signal and ordinary base band level signal, realize better electromagnetic compatibility, this system adopts the photoelectric coupler as signal isolation and interface device of level switch.

TLP121 is the photoelectric coupler that Toshiba produced, isolates impedance as M grade, its drive current of forward direction IF Maximum 20 mA, rear end switch open and make time ‘s s grade, can respond to the request that the error in emasurement of this system pair is not greater than 1 ms. The input interface resistance is set as the adjustable resistance, can adapt to different input voltages.

The pulse signal interface circuit is shown as in Fig Straight line and loop of pulse signal are connected to the forward end 1, 3 pins of TLP121 in Fig of the photosensitive resister ,Rear end 4, 6 pins of TLP121 in Fig Adopt 5V power in the board to pull upward, sends and deals with FPGA to the interface after having a facelift through the Schmidt circuit 74HC14. When the pulse signal is effective, photosensitive resister forward end have electric current flow through, interface circuit export the intersection of high level and ” the 1 ” ; When pulse signal invalid, interface circuit export the intersection of low level and ” the 0 ” .

interface treatment FPGA

Because need to gauge pulse signals of No. 80, it is unable to meet concurrent processing’s demands to adopt the one-chip computer, so choose FPGA and finish the impulse sampling function. Interface deal with FPGA adopt the intersection of Altera and FLEX10K50 of Company, working primary frequency is 6 MHz, the storage chip adopts EPC1PC8.
Its main function has three parts: Frequency demultiplication timer, sampled data buffer, peripheral control logic. FPGA carries on the frequency demultiplication to the main clock, forms cycle as the clock signal of 1 ms. FPGA every ms finishes running side by side and gathers the pulse signals of No. 80 once, leaves the data in the register, send out the interrupt signal to the one-chip computer at the same time, notify the one-chip computer and initiate the data to move, and the time counter within the one-chip computer increases by oneself. The sampled data buffers the module and is used for latching the pulse signals of No. 80 to the internal register at the same time, the one-chip computers every ms all read once. Peripheral control logic is used in the decipher of every control signal of periphery of the one-chip computer, including control register, every chip control the signal interpretation, and the realization of other auxiliary functions.

FM Stereo decoder using TDA7388

A very simple with a compact design FM stereo decoder schematic circuit can be designed using the TDA7388 IC manufactured by ST Microelectronics .
The TDA7338 is a monolithic integrated stereo decoder with noise blanking for FM car radio applications.
With the used BICMOS technique, the 19KHz Notch Filter, the PLL Filter and Phase Filter is realized on the chip with a Switched Capacitor concept.
The TDA7338 stereo decoder contains all necessary functions for processing the MPX signal.
The only external component needed for the PLL is the ceramic resonator for the oscillator which runs at 456kHz.

The pilot detector output is designed as an open collector output, therefore an external pull up resistor is needed. To force the decoder to "MONO" Pin 19 has to be clamped to a voltage below 0.8V.
Selecting VCO-OFF (Pin 7 to GND) the VCO is switched off and the SB and HCC are disabled.
This TDA7338 receiver circuit needs to be powered by a 9 volts DC power supply .

Big Motor Driver TLP250

I have posted a motor controller design that is supposed to be simple, robust, cost effective, and able to handle high currents.  Above is a schematic of the first part of the design.  I will post an updated version to include a PIC to accept commands from a PC, Microcontroller, etc. and provide the direction/PWM signals to the H-bridge.  I am still working on the PCB but here is what I have done so far for review/critism.  What is not shown in the schematic are the in-line fuses for protection.

For the PIC, I use MBasic and PicBasic Pro to write the code.  This should convert easly to the BS2 and PicAxe.


 I updated the schematic again.  As suggested I changed the MOSFET driver to a TLP250 and dropped the 1K resistor across the Gate to source.
Update the schematic to show that the logic grounds are isolated from the dirty motor grounds.

Finished the PCB design.  Once boards are complete will test and post schematic and board files once any kinks are worked out.

I got the prototype boards back from the manufacture two days after I sent them off.  As you'll see below, the quality is excellent.  Tonight I populated the board and checked out functionality with a multimeter prior to testing with a motor.  I managed to get everything put together right so on to the smoke check.  I hooked up a good size motor with a lot of torque and applied power.  The motor moved in both directions and the MOSFET did not even get warm.  This test was applying full power to the motor and not PWM.  Next, I'll write some code and test functionality with PWM hooked to my Oscope so I can check the signals and see how high I can take the frequency.  I'll get around to posting some video but, in the mean time, here are some pictures of one of the finished boards.

Ultimate jewel mod 4N25

My aim was to make a light up jewel (like everyone else) but this jewel had to be different. So basically I set about adding other features and the like to it.
This is what I've come up with and after you’ve read this you'll no doubt have a whole lot of similar, maybe even better ideas based on this design.

What I've ended up with is:
1. A jewel that’s glossy black when the console is off
2. Which glows blue when the console is on
3. Which glows red when there's harddrive activity

Most of these ideas are just transferred from a clear acrylic PC case mod that I did last year!



What you need:
car window tint
spray bottle
small squeegee
Wire - lots of thin gauge wire
4 x red LED’s
4 x blue LED’s
+ The resistors to go with them
For the blue/red LED’s we'll be using the 12volt power source
or if you can, try to get tri-colour LED's, they give you a better effect.
Lots of heatshrink - this is your safest bet as it makes the job incredibly easy and safe IMO
Hairdryer - to heat the heatshrink
Solder and soldering iron
Hot glue gun


Circuit
A piece of strip board
4N25 Opto-isolator
ULN2803 IC
1N4148 Diode
2 x 10K Resistor

A Simple TX for Experimentation 2N7002 project

OK, so back to practical stuff on the bench. I breadboarded a simple push-pull power-oscillator using a pair of 2N7000 MOSFETs, operating in the HF region. (I've attached an LTSpice model if you want to tinker with it, I used a 2N7002 model and asymmetric bias resistors to keep spice happy, the real circuit uses 2N7000s and starts just fine with 4k7 bias resistors on both sides.)

The "180p" capacitor tunes the tapped coil to the frequency of operation, select or make it variable as desired. In one implementation I put 6v8 zener diodes on the MOSFET gates to protect them against over-voltage destruction, at low powers this is not strictly needed, but at higher powers you may need them. Similarly the pair of 33 pF feedback capacitors need to be selected with the frequency of operation in mind. The MOSFET drain breakdown voltage is also important if you are trying to scale up this circuit. While simple, other approaches are probably better for high powers, the MOSFETs are spending a lot of time in their transition regions, dissipating a lot of power. A purely switching class-E approach is obviously better, but suffers from sensitivity of tuning to load impedance in my brief experiments with it (using an IRF510 device). (I've attached another spice model attempting to show the class-E TX approach, I started with values derived using my class-E power amplifier design calculator, as shown it is not perfectly tuned. The practical circuit tunes up nicely and is quite efficient > 70%.) The breadboard TX in the video above is a class-C version with weak capacitive coupling to the tank to optimise its Q. Yet another approach is half or H-bridges, these show great promise, perhaps driving a magnetically coupled "link" winding rather than the tank directly, allowing the tank to float, and facilitating easy variation of coupling to it to optimise its Q... A subject for more detailed investigation at a later date perhaps.

Design on the basis of electrical home appliances liquid crystal display system MC9S08AW32 and HT1621

Drive the performance characteristic of the chip HTl621 and make up the structure, combine and fly to think of Karl’s little controller MC9S08AW32 according to the liquid crystal, have described the design of a kind of electrical home appliances liquid crystal display system. Have described HT1621 practical application in the display system design of this liquid crystal in detail, have explained hardware forming and software design process of this system especially, and provide interface block diagram of the hardware and software flow diagram. The display system of this liquid crystal reveals steadily, fine performance such as low power dissipation, the interface friendship, and saved little controller I/O port resources. 

The display system of the liquid crystal is the important component of the control system of electrical home appliances. The liquid crystal display system of electrical home appliances reveals the module Liquid Crys-tal Display through the liquid crystal Show important information such as its working state and time out, users assign the operation order to deal with to the little controller according to the information, thus realize the control on function of the electrical home appliances. The liquid crystal reveals the module not merely can reveal figure, Chinese character and character vividly, and the consumption is little, the working voltage is low, so the application in the modern electrical home appliances products is more and more extensive. The intersection of electrical home appliances and the intersection of liquid crystal and display system including liquid crystal reveals the module LCD mainly, backlight source, liquid crystal drive the chip HT1621, flies and thinks of Karl’s little controller MC9S08AW32 and button module etc.. Here, according to the performance characteristic, making up structure and programming method, combine MC9S08AW32 of HT1621, have described HT1621 practical application in the liquid crystal display system of electrical home appliances in detail, have explained hardware design and software design process of this system, and provide hardware interface block diagram and software flow diagram of this system.

A liquid crystal drives the chip HT1621 introduction

1. Characteristic of 1 HT1621

HTl621 is held group HOLTEK in Taiwan 128 sections which the company puts out 32* 4The multi-functional driver of the built-in memory, can drive the multistage LCD character to be its main characteristic. HTl621 can form LCD and reveal module and display system, only needs 3- 4 with the communication of little controller, it also included at the same time the electricity orders in a province, reduced the systematic consumption effectively. SSOP that HTl621 is 48 pins encapsulates, has a lot of fine characteristics, its main characteristic is as follows:

1.Working voltage 2. 4- 5. 2 V;
2.Inlay 256 kHz RC oscillator inside;
3.The order can be used in reducing the consumption economizing on electricity;
4.A LCD driver of 32* 4 sections;
5.32* 4 that inlay in one reveal RAM memory;
6.Mode of three kinds of access to data.

1. Systematic structure within 2 HT1621
The systematic structure includes revealing the memory RAM within HT1621 Systematic oscillator, guard the gate the intersection of dog and timer, the intersection of voice and generator and the intersection of LCD and driver,etc.. Only introduce the display memory correlated to this design RAM as follows With LCD driver.

1. 2. 1 reveals the memory RAM
The static behavior reveals the memory RAM, store the data revealed in the form of 32* 4. The data of RAM can shine upon the driver to LCD; The data stored in RAM can use READ, WRITE and READ-MODIFY-WRITE order to visit. Fig. 1 is the image from RAM to LCD driver.

1. 2. 2 LCD driver
HT1621 is one and 128 sections 32* 4LCD driver. It can dispose from software into LCD driver biasing and 2, 3 or 4 public ports of 1/ 2 or 1/ 3. This characteristic makes HT1621 suitable for many kinds of LcD to employ the occasion. LCD drives the clock to be produced from the frequency division of the systematic clock; LcD drives the frequency value of the clock to keep as 256 Hz, it is 32 by the frequency. The shaking brilliantly of 768 kHz, Rc oscillator or external clock in slice are produced; See Table 1 in relevant order of LcD driver.

Runic 100 is ” 100″ Express the order mode type. If carry out the continuous order, except the first order, mode type of other orders yard will be neglected. LCDOFF orders to make LCD bias the generator and fail, thus close LCD to reveal; LCD ON orders to make LCD bias the generator effectively, thus opened LCD to reveal. 

Popular Transistors MMBT3904

This is the MMBT3904 NPN SMT Transistor Design Kit. It includes the very popular SMT version of the 2N3904, General Purpose NPN Transistor: MMBT3904. This was one of the most popular transistors used in all kinds of circuits for years and years. It was designed for general purpose amplifiers with a 500 milliamp Collector current requirement. This kit also includes a few pieces of the MMBT3906 (PNP) which is the complement to the MMBT3904 (NPN) and a SMT Voltage Regulator, LM317M in the SMT package. 


This kit also includes a tremendous amount of different SMT components that you would use to develop numerous circuits. Included are different values of SMT Transistors, SMT Resistors, SMT Aluminum, Ceramic & Tantalum Capacitors, SMT Inductors, SMT Signal (Single & Dual) & Zener Diodes, SMT Trimpots, SMT LEDs, Pushbutton Switches, an Electret Microphone, and a miniature Speaker. It also includes some electronic hardware that are used in most projects for I/O.