SpeedWatt 300W Car Inverter – 110V Power Inverter with Dual USB

The SpeedWatt 300W Car Inverter is a versatile and compact tool ideal for charging various electronic devices on the go. Perfect for travelers, campers, and road-trippers, this inverter offers convenient power for your electronic needs. If you’re searching for an affordable, portable car inverter, the SpeedWatt 300W model is an excellent choice.

Power and Compatibility

The SpeedWatt inverter draws power from two main sources: your car battery or a cigarette lighter outlet, utilizing 12V DC input from either source and converting it into 110V AC power. This converted AC power is then used to charge multiple devices, including phones, laptops, and other electronics, making it suitable for both travel and daily use in homes or offices.

Lightweight and Travel-Ready

Weighing in at just 1.3 lbs, the SpeedWatt inverter is lightweight and highly portable, making it easy to bring along on any trip. Its compact design enhances its portability, ensuring it fits seamlessly into travel bags or car storage compartments without taking up much space.

Durability and Protection

Built to last, this inverter features a robust aluminum housing that protects it from external wear and tear. To further safeguard the internal components, it comes equipped with multiple protective features. An integrated 40A fuse prevents voltage surges, while a quiet cooling fan maintains optimal temperature, preventing overheating.

Why Choose SpeedWatt?

If you’re a frequent traveler or in need of a reliable power source, the SpeedWatt 300W Car Inverter is a top choice. Leveraging advanced technology, this inverter provides dependable performance for charging and powering your essential devices whenever and wherever you need.

Features & Specifications

• 40A Fuse: Built-in protection against voltage fluctuations
• Cooling Fan: Operates quietly for a seamless experience
• Max Temperature: Operates up to 140°F
• Weight: Lightweight at 1.3 lbs
• Input Power: 12V DC
• Output Power: 110V AC, 300W continuous power, with 480W peak power
• Multiple Ports: Includes USB and AC outlets for versatile charging options
• Compact Design: Space-saving and easy to transport

With these features, the SpeedWatt 300W inverter is an efficient, portable, and affordable solution for powering your devices on the go. The built-in fan ensures reliable cooling, and the multiple charging options make it convenient for any situation.

A Travel Essential

According to customer reviews, the SpeedWatt inverter is a reliable and quiet performer. One user mentioned how this 300W inverter became a valuable tool for remote work during COVID-19, allowing him to charge multiple devices simultaneously, including his laptop, GoPro, and mobile devices. Unlike his previous 150W inverter, which was noisy, the SpeedWatt provides a much quieter experience without compromising on performance.

Pros

• Versatile, multi-purpose inverter
• Dual input power sources
• Compact and space-saving design
• Durable aluminum casing
• Lightweight and portable
• Easy to use with dual USB and AC ports
• Ideal for travel, road trips, and camping
• Budget-friendly

Cons

• Short DC adapter cable

With a lengthy list of advantages, the SpeedWatt 300W Car Inverter stands out as a capable and attractive option for those needing reliable power on the go.

Conclusion

In conclusion, the SpeedWatt 300W Car Inverter is a high-performance, affordable option for those needing a dependable power source for camping, travel, or home use. Its compact design, ease of use, and multiple ports make it ideal for charging laptops, phones, and various other gadgets, proving to be an essential addition to any road trip or outdoor adventure.
Source: https://inverterreview.com/speedwatt-300w-car-inverter/

12V 20W Compact High Performance Stereo Amplifier Circuit project with schematic and explanation

Amplifiers which run from 12V DC generally don’t put out much power and they are usually not hifi as well. But this little stereo amplifier ticks the power and low distortion boxes. With a 14.4V supply, it will deliver 20 watts per channel into 4-ohm loads at clipping while harmonic distortion at lower power levels is typically less than 0.03%. This is an ideal project for anyone wanting a compact stereo amplifier that can run from a 12V battery. It could be just the ticket for buskers who want a small but gutsy amplifier which will run from an SLA battery or it could used anywhere that 12V DC is available – in cars, recreational vehicles, remote houses with 12V DC power or where ever.

20W Stereo Audio Amplifier Image:

Because it runs from DC, it will be an ideal beginner’s or schoolie’s project, with no 240VAC power supply to worry about. You can run it from a 12V battery or a DC plugpack. But while it may be compact and simple to build, there is no need to apologise for “just average” performance. In listening tests from a range of compact discs, we were very impressed with the sound quality. Long-time readers might recall that we presented a similar 12V power amplifier design back in May 2001. It was a similar configuration to this one but it is now completely over-shadowed by the much lower distortion and greatly improved signal-to-noise ratio of this new design. In fact, let’s be honest: the previous unit is not a patch on this new design. It used two TDA1519A ICs which resulted in distortion figures above 1% virtually across the board and a signal-to-noise ratio of only -69dB unweighted.

20W Stereo Amplifier Circuit:

 

However, by using the TDA­7377 power amplifier IC and making some other improvements, the THD (total harmonic distortion) of the new design is about 50 times better than the older unit (see performance graphs for details). The bottom line is that the THD under typical conditions is around just 0.03% or less. It is also able to deliver more output power due to the improved output transistors in the new power amplifier IC. In addition, its idle power consumption is low – not much more than 1W. As a result, if you don’t push it too hard it will run cool and won’t drain the battery too quickly. And because the IC has self-protection circuitry, it’s just about indestructible. It will self-limit or shut down if it overheats and the outputs are deactivated if they are shorted.

20W Stereo Amplifier Circuit Diagram:

With a 12V supply, the largest voltage swing a conventional solid-state power amplifier can generate is ±6V. This results in a meagre 4.5W RMS into 4O and 2.25W RMS into 8O, without considering losses in the output transistors. Even if the DC supply is around 14.4V (the maximum that can normally be expected from a 12V car battery), that only brings the power figures up to 6.48W and 3.24W for 4O and 8O loads respectively – still not really enough. There are three common solutions to this problem. The first is to boost the supply voltage using a switchmode DC converter. This greatly increases the cost and complexity of the amplifier but it is one way of getting a lot of power from a 12V supply. However, we wanted to keep this project simple and that rules out this technique.

Parts layout:

There are variations on the boosting method, such as the class H architecture used in the TDA1562Q IC featured in the Portapal PA Amplifier (SILICON CHIP, February 2003). It is able to achieve 40W/channel but with >0.1% THD. In that case, the amplifier output itself provides the switching for a charge pump. The second method is to lower the speaker impedance. Some car speakers have an impedance as low as 2O, which allows twice as much power to be delivered at the same supply voltage. However, we don’t want to restrict this amplifier to 2O loudspeakers.

Author: Nicholas Vinen - Copyright: Silicon Chip

Precision Amplifier With Digital Control Circuit project with schematic and truthtable

This circuit is similar to the preceding circuit of the attenuator. Gain of up to 100 can be achieved in this configuration, which is useful for signal conditioning of low output of transducers in millivolt range. The gain selection resistors R3 to R6 can be selected by the user and can be anywhere from 1 kilo-ohm to 1 meg-ohm. Trimpots can be used for obtaining any value of gain required by the user. The resistor values shown in the circuit are for decade gains suitable for an autoranging DPM. Resistor R1 and capacitor C1 reduce ripple in the input and also snub transients. Zeners Z1 and Z2 limit the input to ±4.7V, while the input current is limited by resistor R1. Capacitors C2 and C3 are the power supply decoupling capacitors.

Precision Amplifier With Digital Control Circuit Diagram:

Op-amp IC1 is used to increase the input impedance so that very low inputs are not loaded on measurement. The user can terminate the inputs with resistance of his choice (such as 10 megohm or 1 meg-ohm) to avoid floating of the inputs when no measurement is being made. IC5 is used as an inverting buffer to restore polarity of the input while IC4 is used as buffer at the output of CD4052, because loading it by resistance of value less than 1 meg-ohm will cause an error. An alternative is to make R7=R8=1 meg-ohm and do away with IC4, though this may not be an ideal method.

Gains greater than 100 may not be practical because even at gain value of 100 itself, a 100μV offset will work out to be around 10 mV at the output (100μV x 100). This can be trimmed using the offset null option in the OP07, connecting a trimpot between pins 1 and 8, and connecting wiper to +5V supply rails.For better performance, use ICL7650 (not pin-compatible) in place of OP07 and use ±7.5V instead of ±5V supply.Eight steps for gain or attenuation can be added by using two CD4051 and pin 6 inhibit on CD4051/52. More steps can be added by cascading many CD4051, or CD4052, or CD4053 ICs, as pin 6 works like a chip select. 

Some extended applications of this circuit are given below.
1. Error correction in transducer amplifiers by correcting gain.
2. Autoranging in DMM.
3. Sensor selection or input type selection in process control.
4. Digitally preset power supplies or electronic loads.
5. Programmable precision mV or mA sources.
6. PC or microcontroller or microprocessor based instruments.
7. Data loggers and scanners.

Author : Anantha Narayan - Copyright : EFY

Class-A Headphone Amplifier Circuit project with schematic and explanation

This circuit is derived from the Portable Headphone Amplifier featuring an NPN/PNP compound pair emitter follower output stage. An improved output driving capability is gained by making this a push-pull Class-A arrangement. Output power can reach 427mW RMS into a 32 Ohm load at a fixed standing current of 100mA. The single voltage gain stage allows the easy implementation of a shunt-feedback circuitry giving excellent frequency stability.

Class-A Headphone Amplifier Circuit diagram:

The above mentioned shunt-feedback configuration also allows the easy addition of frequency dependent networks in order to obtain an useful, unobtrusive, switchable Tilt control (optional). When SW1 is set in the first position a gentle, shelving bass lift and treble cut is obtained. The central position of SW1 allows a flat frequency response, whereas the third position of this switch enables a shelving treble lift and bass cut.

Note:

• Before setting quiescent current rotate the volume control P1 to the minimum, Trimmer R6 to zero resistance and Trimmer R3 to about the middle of its travel.
• Connect a suitable headphone set or, better, a 33 Ohm 1/2W resistor to the amplifier output.
• Connect a Multimeter, set to measure about 10Vdc fsd, across the positive end of C5 and the negative ground.
• Switch on the supply and rotate R3 in order to read about 7.7-7.8V on the Multimeter display.
• Switch off the supply, disconnect the Multimeter and reconnect it, set to measure at least 200mA fsd, in series to the positive supply of the amplifier.
• Switch on the supply and rotate R6 slowly until a reading of about 100mA is displayed.
• Check again the voltage at the positive end of C5 and readjust R3 if necessary.
• Wait about 15 minutes, watch if the current is varying and readjust if necessary.

Parts List :

P1          : 22K  Dual gang Log Potentiometer 
R1          : 15K 
R2          : 220K
R3          : 100K
R4          : 33K 
R5          : 68K 
R6          : 50K 
R7          : 10K 
R8,R9       : 47K 
R10,R11     : 2R2 
R12         : 4K7
R13         : 4R7
R14         : 1K2
R15,R18     : 330K
R16         : 680K
R17,R19     : 220K
R20,R21     : 22K
C1,C2,C3,C4 : 10µF/25V 
C5,C7       : 220µF/25V
C6,C11      : 100nF
C8          : 2200µF/25V
C9,C12      : 1nF
C10         : 470pF
C13         : 15nF
D1          : LED
D2,D3       : 1N4002 
Q1,Q2       : BC550C 
Q3          : BC560C  
Q4          : BD136   
Q5          : BD135   
IC1         : 7815
T1          : 15CT/5VA Mains transformer
SW1         : 4 poles 3 ways rotary Switch 
SW2         : SPST slide or toggle Switch

Very simple 18Watt Audio Amplifier Circuit project with schematic and explanation

High Quality very simple unit No need for a preamplifier.

18Watt Audio Amplifier Circuit Diagram:

Amplifier parts:
  
P1____22K  Log. Potentiometer (Dual-gang for stereo) 
R1___1K  1/4W Resistor 
R2___4K7 1/4W Resistor 
R3___100R  1/4W Resistor 
R4___4K7 1/4W Resistor 
R5___82K  1/4W Resistor 
R6___10R  1/2W Resistor 
R7___R22  4W Resistor (wirewound) 
R8___1K  1/2W Trimmer Cermet (optional) 
C1___470nF  63V Polyester Capacitor 
C2,C5___100µF   3V Tantalum bead Capacitors 
C3,C4___470µF  25V Electrolytic Capacitors 
C6___100nF  63V Polyester Capacitor 
D1___1N4148  75V 150mA Diode 
IC1___TLE2141C  Low noise, high voltage, high slew-rate Op-amp 
Q1___BC182  50V 100mA NPN Transistor 
Q2___BC212  50V 100mA PNP Transistor 
Q3___TIP42A  60V 6A    PNP Transistor 
Q4___TIP41A  60V 6A    NPN Transistor 
J1___RCA  audio input socket

Power supply :

18Watt Audio Amplifier Power Supply

Power supply parts: 
R9___2K2 1/4W Resistor 
C7,C8___4700µF 25V Electrolytic Capacitors 
D2___100V 4A Diode bridge 
D3___5mm. Red LED 
T1___220V Primary, 15 + 15V Secondary, 50VA Mains transformer 
PL1___Male Mains plug 
SW1___SPST Mains switch

Notes:

• Can be directly connected to CD players, tuners and tape recorders.
• Do not exceed 23 + 23V supply.
• Q3 and Q4 must be mounted on heatsink.
• D1 must be in thermal contact with Q1.
• Quiescent current (best measured with an Avo-meter in series with Q3 Emitter) is not critical.
• Adjust R3 to read a current between 20 to 30 mA with no input signal.
• To facilitate quiescent current setting add R8 (optional).
• A correct grounding is very important to eliminate hum and ground loops. Connect to the same point the ground sides of J1, P1, C2, C3 & C4. Connect C6 to the output ground.
• Then connect separately the input and output grounds to the power supply ground.

Technical data: 
Output power: 
    18 Watt RMS into 8 Ohm (1KHz sine wave) 
Sensitivity: 
    150mV input for 18W output 
Frequency response: 
    30Hz to 20KHz -1dB 
Total harmonic distortion @ 1KHz: 
    0.1W 0.02% 1W 0.01% 5W 0.01% 10W 0.03% 
Total harmonic distortion @10KHz: 
    0.1W 0.04% 1W 0.05% 5W 0.06% 10W 0.15% 
Unconditionally stable on capacitive loads 

Source : RedCircuits