1000W Power Inverter Circuit

Here’s a circuit for the power inverter circuit based MOSFET RFP50N06. The inverter capable to handle loads up to 1000W, it’s depended on your power inverter transformer. Here’s the figure of the circuit;

The RFP50N06 Fets are rated at 50 Amps and 60 Volts. Heat sink is required for cooling the MOSFETs. You may add some MOSFETs with parallel connection to get more power. It is recommended to have a “Fuse” in the Power Line and to always have a “Load connected”, while power is being applied.

Stable Zener Reference Circuit

Nowadays some first-rate voltage references are available. Take the LM385 for example: this is available for different voltages and even comes in an adjustable version. What is more, the current consumption may be kept very small (10 µA). But as often happens, you may not have one to hand when you need one for an experimental circuit. In that case, you could use an ordinary zener diode for the reference. Unfortunately, they have a somewhat higher internal resistance (about 5?), which means they won’t be very stable when the supply voltage varies. The solution is right in front of us: use the stabilized zener voltage as the supply voltage! This is obviously only possible if the stabilized voltage is higher than the zener voltage. This is the figure of the circuit of stable zener reference;

It therefore has to be amplified a little. This is exactly what this circuit does: it amplifies it by a factor of two. The current limiting resister should be chosen such that a current of 1 to 3 mA flows through the zener diode. Manufacturers usually state the zener voltage at a current between 3 to 5 mA. The zener diode is fed from a stabilized voltage and hence has a very stable operating point, which is independent from the supply voltage. The graph speaks for itself. It is clear that the output voltage is much more stable. The graphs have been plotted to different scales to make the comparison easier. In reality the op amp output is twice the zener voltage. Zener diodes also have a temperature coefficient, which is smallest for types with a zener voltage around 5 volts. Virtually any type of opamp should be suitable; even our old friend the 741 works well enough.

Tachometer Circuit Using LM2907 LM2917 Frequency to Voltage Converter

This is a design circuit for tachometer circuit based on the LM2907 IC can be used to provide zero crossing datum to a digital system. At each zero crossing of the input signal the charge pump changes the state of capacitor C1 and provides a one-shot pulse into the zener diode at pin 3. The width of this pulse is controlled by the internal current of pin 2 and the size of capacitor C1 as well as by the supply voltage. This is the figure of the circuit;

Since a pulse is generated by each zero crossing of the input signal we call this a ``two-shot'' instead of a ``one-shot'' device and this can be used for doubling the frequency that is presented to the microprocessor control system. This electronic tachometer circuit project can be powered from a 12, 15 volt DC power supply circuit. Input can be from plus /minus 20 mV to plus/minus 28V. Pulse width is equal with (VCC/2)x(C1/I2) and the Pulse height is equal with VZENER.

Frequency/Tone Decoder Circuit Using TC9400 FVC

Another application of FVC (frequency-to-voltage converter) is tone/frequency decoder. This circuit is used to determine the frequency band of an oscillation signal. This circuit is used in many application like determines the frequency band in the signal and remote control where the frequency band corresponds to a different command. This circuit uses TC9400 F/V converter to convert the frequency to voltage because the frequency must be converted to proportional analog voltage before can be detected. This is the figure of the circuit;

Beside TC9400 F/V converter, this circuit also uses the quad comparators. It used to detect when the frequency limits is exceeded by the voltage (frequency). The frequency is indicated by the logical “1″ at any of the five output. [Circuit diagram source: Microchip Application Note]

Automotive 12V to +-20V Converter Circuit (for Audio Amplifier)

The limitation of car supply voltage (12V) forces to convert the voltages to higher in order to power audio amplifiers. In fact the max audio power x speaker (with 4 ohm impedance) using 12V is (Vsupply+ - Vsupply-)^2/(8*impedance) 12^2/32 = 4.5Watts per channel. This is the figure of the circuit diagram;

The transformer must be designed to reduce skin effect, it can be done using several insulated magnet wire single wires soldered together but conducting separately. The regulation is done both by the transformer turn ratio and varying the duty cycle. In my case i used 5+5 , 10+10 turns obtaining a step up ratio of 2 (12->24) and down regulating the voltage to 20 via duty cycle dynamic adjust performed by the PWM controller TL494. The step-up ratio has to be a little higher to overcome diode losses, winding resistance and so on and input voltage drop due to wire resistance from battery to converter. The output capacitors are 4700uF 25V, not very big, since at high frequency the voltage ripple is most due to internal cap ESR fortunately general purpose lytics have enough low esr for a small ripple (some tens of millivolts). Also at high duty cycle they are feed almost with pure DC, giving small ripple. This supply given me up to 85% efficiency (sometimes even 90% at some loads) with an input of 12V because i observed all these tricks to keep it functional and efficient. An o-scope would be useful, to watch the ripple and gate signals (watching for overshoots), but if you follow these guidelines you will avoid these problems.

Sound to Dancing Lights Converter Circuit

This is a design circuit for converting an audio signal (such as one that comes from the speaker terminals of a CD player). The circuit basically consists of a buffer/amplifier stage and three filter circuits: a high-pass filter, a mid-pass filter, and a low-pass filter. The output of each filter circuit drives a light-emitting diode of different color. This is the figure of the circuit;

The input signal is fed to the buffer stage through C1. The values of RF and RV1 should be chosen so that the buffer is able to drive the three filters attached to its output.  The low-frequency, mid-frequency, and high-frequency components of the input signal are only allowed to pass through the low-pass filter (bottom filter), the mid-pass filter (middle filter), and the high-pass filter (topmost filter), respectively, thus separating them from each other. Changes in the output of a filter cause its corresponding output LED to turn on and off.  In effect, feeding a continuous audio signal to the input of this circuit causes the LED's to 'dance'.

DTMF Decoder Circuit For PC

This is a design circuit for decoder circuit that can be use for DTMF circuit for PC. This is the figure of the circuit;

Our DTMF decoder can be powered from a 9V battery or from your parallel printer port. It can detect and display all 16 DTMF digits on your computer screen in real-time. The Window's program can be placed in the minimize mode and still detect tones while you use your computer to do other things like We are now in the process of adding an DTMF decoder which will interface to the sound card game port.

Infrared Remote Control Decoder Circuit

This is a circuit for infrared Remote Control Decoder circuit. This circuit uses the SAA3049A which is used to check and convert the received coded data (RECS80/RC5) into latched binary outputs. This is the figure of the circuit;

We can uses several device in one location because the device address can be hard-wired for a particular address. The output of this device are the received data and address. This device has several feature such as it is suitable for low SAA3049A and low voltage supply current applications, it can accept RC5 codes with bi-phase transmission (SAA3006, SAA3010) or RECS80 codes with pulse position modulation (SAA3004, SAA3007, SAA3008) and it can Decodes 64remote control commands with a maximum of 32 sub-addresses. Besides that a maximum commands of this device is up to 2048 by adding  circuitry for binary decoding, for example 1-of-16 decoder (HEF4515). 

[Schematic source: NXP Semiconductor Application Notes]

An Alternative Approach to Higher-Power Boost Converters

This is a design circuit for high power boost converter circuit. This circuit is control by LM25037 Single chip IC. This circuit is a simple straightforward approach that can provide benefits over using a typical single gate-drive controller. This is the figure of the circuit;

The benefits can include higher step-up ratios and lower FET losses due to the reduction in transitional losses. Although there are a number of possible approaches to reduce total FET losses in higher-power boost converters, the equations in this article can be used to calculate total losses in the boost FETs for a number of different approaches. Considering the 150W boost converter example, it has been shown that total losses in the FETs are reduced when comparing the LM25037 dual-output gate-drive controller with the LM5020 single-output gate-drive controller.

[Schematic diagram source: National Semiconductor Notes]

A/D Conversion Circuit for Single-Ended MSB First Mode

This is a design circuit for analog to digital converter that can be used in data acquisition. This circuit is based on ADC0833 and controlled by INS8048. Before explaining the system configuration, it is worthwhile for one to understand the operation of the INS8048 processor's I/O ports. Ports 1 and 2 are quasi-bidirectional; that is, they can be used as inputs or outputs while being statically latched. If a ``1'' is written into any port bit, that bit can function as an input or as a high level output. If a ``0'' is written into any port bit, that bit can function only as a low level output.

Outputs are latched until changed and inputs are unlatched and must be read immediately. When used with the ANL Pp, A (AND accumulator to port) or the ORL Pp, A (OR accumulator to port) instructions, these ports provide an efficient means of handling single line inputs and outputs. Port expansion, if anticipated, is handled via the lower four bits of Port 2. Only four pins of the processor's Port 1 or Port 2 are needed for physical interfacing. The ANL or ORL instructions set up the port pins to produce the proper outputs (CS, CLK, and the multiplex address) or to allow for data input from the A/D converter.

[Circuit schematic source: National Semiconductor Notes].

Low Voltage Synchronous Buck Feedback

This is one of the application for low voltage feedback in PWM. This circuit is called as synchronous buck feedback. This circuit is proposes an alternate method for feeding back an output voltage lower than the PWM internal error amplifier reference voltage. This is the figure of the circuit.


Normally the output voltage is higher than the error amplifier reference, and so a simple resistive divider between VOUT and ground sets the regulated voltage at the non-inverting input of the PWM error amplifier. However, when VOUT is less than the error amplifier reference voltage, the feedback voltage must be divided up instead of down. Dividing up implies that some additional voltage must be added to the feedback from another regulated voltage source.[Schematic’s source: Texas Instrument Notes].

Positive to Negative Converter Using Direct Feedback

This is a design circuit for positive to negative converter. The negative feedback (NFB) pin, enables negative output regulators to be designed using direct feedback. In the circuit shown in Figure 3, a 2.7 V to 13 V input, –5 V output converter, the output is monitored by the NFB pin and a simple divider network. No complex level shifting or unusual grounding techniques are required. The S/S pin is used to synchronize the switching frequency to a 600 KHz external clock signal. This is the figure of the circuit.


The switch clamp diodes, D2 and D3, prevent the leakage spike from the transformer, T1, from exceeding the switch’s absolute maximum voltage rating. The Zener voltage of D2 must be higher than the output voltage, but low enough that the sum of input voltage and clamp voltage does not exceed the switch-voltage rating.

DC to DC Converter Circuit

This is a design for DC to DC converter module. The module is a device that accepts a DC input voltage and produces a DC output voltage. Normally the output voltage produced is at a different voltage level than the input. DC to DC converters are used to provide noise isolation as well as power bus regulation. In this circuit, converter is using LTM4600. Look to the figure of the circuit.


The 10A High efficiency DC/DC converter module LTM4600 is a complete 10A, DC/DC step down power supply. Included in the package are the switching controller, power FETs, inductor, and all support components. Operating over an input voltage range of 4.5V to 20V, the LTM4600 supports an output voltage range of 0.6V to 5V, set by a single resistor. This high efficiency design delivers 10A continuous current, needing no heat sinks or air flow to meet power specification. Only bulk input and output capacitors are needed to finish the design.

Tone Generator Circuit Using 555 IC

This tone generator circuit is a basic 555 square wave oscillator that is used to produce a 1 Khz tone from an 8 ohm speaker. There are two type of circuit that can be using. Each the type have same characteristic, but have different operation. This is the both circuit that can be studied in this figure.


Operation circuit in the circuit on the left, the speaker is isolated from the oscillator by the NPN medium power transistor which also provides more current than can be obtained directly from the 555 (limit = 200 mA). A small capacitor is used at the transistor base to slow the switching times which reduces the inductive voltage produced by the speaker. Frequency is about 1.44/(R1 + 2*R2)C where R1 (1K) is much smaller than R2 (6.2K) to produce a near square wave. Lower frequencies can be obtained by increasing the 6.2K value, higher frequencies will probably require a smaller capacitor as R1 cannot be reduced much below 1K. Lower volume levels can be obtained by adding a small resistor in series with the speaker (10-100 ohms).

In the circuit on the right, the speaker is directly driven from the 555 timer output. The series capacitor (100 uF) increases the output by supplying an AC current to the speaker and driving it in both directions rather than just a pulsating DC current which would be the case without the capacitor. The 51 ohm resistor limits the current to less than 200 mA to prevent overloading the timer output at 9 volts. At 4.5 volts, a smaller resistor can be used.

Definition ADC

ADC is a circuit formed in a single functioning chip to change analog signal becomes digital signal. In general we apply chip ADC 8 beet to change analog signal stretch 0-5 V becomes digital level 0-255 for ADC 8 beet. At the moment have also been in big supply ADC capable to work for data process 12 bits.

To do converting there are two methods. First method is use a Flash ADC. This method also is recognized as parallel ADC as easiest circuit to be studied. This method formed by using a group of comparator comparing input signal to reference strain applies op-amp. Resistor applied Resistor must having high tolerance that more accurate.

Second method is method Successive Approximation. This method applies approach successively to look for value that is most precise. This register calculates by trying to all bit values started from MSB and terminated with LSB. During calculation process, register will monitor comparator output to see if calculation of binary is less or bigger than input signal.

Analog To Digital Converter

ADC is a circuit formed in a single functioning chip to change analog signal becomes digital signal. In general we apply chip ADC 8 beet to change analog signal stretch 0-5 V becomes digital level 0-255 for ADC 8 beet. At the moment have also been in big supply ADC capable to work for data process 12 bits.

To do converting there are two methods. First method is use a Flash ADC. This method also is recognized as parallel ADC as easiest circuit to be studied. This method formed by using a group of comparator comparing input signal to reference strain applies op-amp. Resistor applied Resistor must having high tolerance that more accurate.

Second method is method Successive Approximation. This method applies approach successively to look for value that is most precise. This register calculates by trying to all bit values started from MSB and terminated with LSB. During calculation process, register will monitor comparator output to see if calculation of binary is less or bigger than input signal.

Thermal Voltage Converter

This application can give a construction electronic thermal that can operate from 00 up to 240 C. This circuit can producing output approximately about 500 mV/0 C, that can be read in the voltmeter after calibrate with temperature. To make this application to be a simple circuit, the temperature detector we can give thermystor with negative temperature coefficient (NTC).

This profit for the application, the resistance temperature coefficient is very large, but the temperature coefficient is not constant and the output voltage temperature circuit can’t be linier. In 00 up to 240 area, the linier is enough for a simple temperature.

IC op-amp is connected used to be differential amplifier. Input transmitting by bridge circuit that consists of R1 to R4. The constant of bridge arm can form by R1, R2, R3 and P1, but R4 is to form the variable arm. The voltage in R1 and R2 is 3, 4 volt. Within the increasing of the temperature, the NTC resistance will decrease and the voltage will fall and make the output op-amp increase. If the output can’t precision in 0, 5 V0/C, the value R8 and R9 can appropriately, but both of them have been same.

IC that can use to this application is 741, 3130, or 3140. Compensation capasitor C2 isn’t necessary if we use IC 741, because this IC can compensate. R4 can use NTC 10K, but for small type will give respond faster cause have lower thermal inertial.