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

Mono Power Amplifier A1015, BD140 ,TIP2955

Mono Power Amplifier - A1015, BD140 ,TIP2955 Circuit Diagram


Typically audio amplifier stereo amplifier to a two amplifier. And if a mono amplifier is a single speaker. However this circuit command be present extended to the mono two loudspeaker.But not a equivalence or else serialization access.This makes it needless impedance of the speaker has altered.But will remain to utilize the spokeswoman as a replacement for of the resistance - Collection Peter (RC) of the transistor.The circuit can be alive prolonged to 2 loudspeaker itself.

What time raising the power supply circuit and the audio to input. the audio sign coupling to through the C1 and R1 to increase with the Q1.Which Q1 serves like the Regional Pre amp amplifier to power up to a one point.already conveyance it to Q2.Which Q2 is connected to emitter follower circuit.be active as a driver amplifier intimate section from the pre amp section provides added power to drive the Q3 perform. and Q3 motivation provide while a Regional Power amp amplifier output to the spokeswoman.The opinion of the audio intimate through the VR1 and R2 to enter the pin B of Q2.To control the stability of working instead of well brought-up.This circuit is an output of 40 milliwatts watts of distortion of the gesture rate is by the side of 0.1 percent.And frequency response from 15 Hz - 200 kHz.

Flyback converter VIPER12A

Hi,
I've been trying to come up with a really small design that will take mains line voltage in the range of 90-250 volt a/c - 50/60 Hz and output
5 / 3.3volt at < 500mA.

I don't want to use a big transformer+linear regulator because of the size !

I've seen implementations like Microchip AN954, (capacitive and resistive PSU):



Then I located the ViPer family of devices from ST, specifically the VIPER12A which can handle a bulk and flyback configurations.
It provides some sort of protection and I like them, they come in DIP package and most important I can source them in my town !

From the app note "AN1484":
The circuit is a standard Flyback converter with secondary current and voltage regulation driving the VIPer12A feedback pin through an optocoupler.

This is the design I was looking for !, it's small, safe and it's been used all over the world but I know nothing about them  :o,
I feel I'm going through the rabbit hole and things get complicated every step of the way.
First and most important it's very hard to find the correct flyback transformer, the two vendors I found don't have a sales webpage they work only
through distributors, and even then I'm not sure about the stock.

The MC44603P 750w power problems 20N60

burn the IGBT control

IGBT with a 20N60

Anyboday can help?

Thank you!

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.

Driving Circuits from a CR2032 Lithium Coin Cell

Recently I have tested an complete over the top design which pushed the poor little CR2032 far beyond its limits. Time to grab a few facts from the datasheet for further reference.

To get a good example I found a quite elaborate CR2032 datasheet from Duracell. I think other batteries behave quite similar to this.

The general key fact of an CR2032 are obvious and quite easy to grab from the datasheet:

Voltage: 3V

Capacity: 240mAh (to 2.0V)

If you study the datasheet more closely you will see that the voltages drop sharply after it reaches 2.8V (after it has delivered about 170mAh).

ESR (Equivalent Series Resistor):about 18 to 20 Ohms.

The ESR (Equivalent Series Resistor) or IR (Internal Resistance) is quite flat up to 150mAh of capacitance – there it reaches about 20 Ohms. At 170mAh it reaches something like 30 Ohms. This is quite hefty. In comparison good capacitors have a series resistance from some Ohms to a fraction of an Ohm – so it is always good to put some (even electrolytic) capacitors in parallel to the battery. If you are concerned that switching on or of of your circuits discharges the battery to much by charging up the capacitors – there is a simple trick to prevent it: put the capacitors in front of the ‘on’ switch so that are always charged and will not charge after your circuit is switched on. The leakage current will be so small that it will be neglectable in most cases.

But if you want to calculate how much constant current you can draw from these batteries you have to use Ohm’s law:

V = R * I or I = V /R

If you take the later and say you want no voltage drop higher that 1.2 Volts – because after that your circuit reaches 1.8 Volts which makes your microcontroller most probably going brown out. Applying these with the ESR of 20 Ohms, you will get something like 60 mA you can draw by them (I = 1.2V/20Ohm). You if calculate more conservative and do not want to go below 2.8V – which gives you some 0.2 Volts head room  – you will only be able to draw 10 mA (I = 0.2V/20Ohm) – just enough for an LED. These calculations do not consider the voltage drop of the battery of its life time.

In the bottom line: If you use those batteries you have to consider the 20-30 Ohms series resistance. Especially if you draw some constant current (spikes can be easily removed using capacitors). Yo have to assume 170mAh as maximum capacitance because then the CR2032 reaches 2.8Volts and the ESR goes up to a whopping 30 Ohms – going up from there very steep. Because of the high ESR of the CR2032 you will most probably not be able to draw more than 20-30 mAh safely (as constant current).

Perhaps it is even better to get a boost converter to 3 or 3.3V – to suck out all the juice in the battery. This should should be good for the environment too. Or even better get rechargeable Lithium Cells.

So driving an RGB with an 5V boost op converter is impossible. At white (all three LEDs draw 20mA) it is 60mA current at 5V, considering a efficiency of 80% this will give you more than 120 mAh at 3.3V. Impossible or the CR2032. So my intended design will never work. I wish I had done those calculations before I designed it and not after I saw that the prototype does not work.


As we see the higher the current is the more loss we get by the ESR of 20 Ohms. So the question is how much power we can get from an CR2032. If we want to draw the maximum amount of power over a short time we simply take the power:

P=V*I

And we know that the voltage is

v=3-20*I

And we get

P=(3-20*I)*I

If we create a little graph from it we get

So we see that the maximum is somewhere at 75mA and somwhere at 0,1125 Watts. Perhaps the real theoretical value is a bit off – but most real batteries will be a bit off too, so it is a good enough aproximation.

So that is somewhat consistent to our previous calculations to not exceed 80mA to avoid a too big voltage drop.

But how many energy can we draw from an CR2032? For this we simply calculate the watt hour of the battery:

e=P*t and t=0,24A/I

so we get

e=(0,24/I)*P

or

But this is not very astonishing. The less current you draw the less loss you got at the internal resistor. But I am unsure if there is this resistor, which burns energy to heat. But since the batteries get hot if you draw too much power you will get some loss. But I do not think that the loss is equal to a 20 Ohm resistor. But the main finding is clear – the more current you draw the more loss you have.

From the comments I got the tip to put the lithium coin cells in series to get a higher coltage at the current draw. But this will enlarge the voltage swing at different current levels (from 6V at 0mA to 3V at 150mA). This can be dangerous for your circuit. A better approach would be to put the batteries in parallel to half the internal ESR – so you would still get 1.5 Volts at 150mA.

Of course to counter current spikes you should allways put sufficiently sized capacitors in parallel. Sufficiently sized depends on the level of current spikes and there time. Just check out how a Farad is defined and you can derrive the needed value (which is the product of voltage change and time).

But in most of my designs space is a rare good. So no parallel batteries and no big capacitor banks.

Something that could work is sucking the power with a boost converter to get a steady output voltage independent of the current draw. This would of course enhance the loss but at least we get the voltage we want at an expense of the efficiency.

Circuit Power Amplifier OTL 50W by 2N3055

If you are seeking power Amplifier at loud good sound , durable and economize. I begs for to advise Circuit Power Amplifier OTL 50Watt by 2N3055 , because of use the equipment that seek good easy and build not difficult with. Many you who tell amp OTL the sound is not good. Me chest edge that be not the loud sound is excellent. Then like to use general ( in the past ) although in contain divide still have use. I like it fining decorates the circuit. Just you feed power supply 50V 2A also the work has already and a loudspeaker should use 8ohm 12 inc. sizes. Besides still model PCB for the convenience of friends. Request have fun Power Amplifier OTL 50Watt , please sir.

Multi-purpose dual power supply regulator board AMS1117

All embedded systems require electric power to operate. Most of the electronic components inside them, including the processors, can operate at a wide range of supply voltage. For example, the operating voltage range for the PIC16F1847 microcontroller is 2 to 5.5 V. But there are certain applications where you need a regulated constant voltage to avoid malfunctioning of the circuit or getting erroneous results. For instance, any application that involves analog-to-digital conversion (ADC) requires a fixed reference voltage to provide accurate digital count for input analog signal. If the reference voltage is not stable, the ADC output is meaningless. Here is my latest dual power supply regulator board that provides constant 3.3V and 5.0V outputs from an unregulated DC input (6.5-10V). It is small in size and can be easily enclosed inside the project box along with a project circuit board. It can also be used to power test circuits on breadboard. The board uses two AMS1117 series fixed voltage regulators and receives input power through a DC wall wart or an external 9V battery.

he regulator circuit uses two AMS1117 series fixed voltage regulators, AMS117 5.0 and AMS1117 3.3, to derive constant 5.0V and 3.3V outputs from an unregulated DC input voltage. The circuit diagram of the board is shown below.

Note that both AMS1117-3.3 and AMS1117-5.0 derive input power directly from the unregulated supply voltage, which means each of them can deliver up to 0.8A of current. However, for this particular board it is recommended to limit the output current up to 500 mA maximum. For the safety of the AMS1117-3.3 regulator IC, the unregulated input voltage is also recommended to be within 6.5 to 10.0 V. This board is best to use in a project that is designed tobe powered with a 9V DC from either a PP3 battery or a wall adapter. The PCB is only 1.9″ x 1.4″, and occupies a small area inside the project box.

 

The board doesn’t have any ON/OFF switch, because it may not be useful if this board is enclosed inside the project box. But through-hole pads are provided on the board if you want to add one externally. There are two surface mount pads which are shorted together by default with solder to close the circuit permanently. These must be disconnected if an external ON/OFF switch has to be added.

The regulated output voltages (5V and 3.3V) are accessed through screw terminal blocks. This power supply board can also be used to power breadboard circuits (see the picture below).

 

Power Pulse Generator THE LM150/LM250/LM350

Power Pulse Generator THE LM150/LM250/LM350 is an adjustable voltage regulator capable of delivering from 1.2 to 33 volts at a maximum current of 3 amperes. Normally this chip is used in both fixed and adjustable power supplies, voltage regulators and voltage references. Since I'm always looking for a new way to obtain high-current pulses for flashing lamps and driving motors, motors, I have recently been experimenting with ways to switch the output of the LM350T on and off. Since the output voltage of this chip is fully adjustable, a circuit which switches its output on and off provides a variable- amplitude power pulse generator. Before looking at an LM350T power pulse generator, let's first examine the operating characteristics of this versatile chip. Figure 2-42 shows the pin diagrams for both the TO-220 packaged LM350T and the TO-3 versions of the LM150/LM250//LM350. The chip requires a minimum of external components.