Showing posts with label using. Show all posts
Showing posts with label using. Show all posts
Monday, September 2, 2013
1W Audio Amplifier Using NCP2830
This 1w audio amplifier circuit is designed using NCP2830 audio IC manufactured by ON Semiconductor.This audio power amplifier ic designed for portable communication device applications and require few external electronic components.
1W Audio Amplifier Circuit using NCP2830
NCP2830 is capable to provide 1W continuous output power in 8 ohms load.NCP2830 audio power amplifier main features are : high quality audio (THD+N = 0.04%) , low noise: SNR up to 100 dB, overall system efficiency optimization: up to 89% , Superior PSRR (−88 dB): Direct Connection to Battery , Very Low Quiescent Current 7 mA , Optimized PWM Output Stage: Filterless Capability , Selectable gain of 2 V/V or 4 V/V .
1W Audio Amplifier Circuit using NCP2830
Thursday, April 11, 2013
Fire alarm using thermistor NE555
Many fire alarm circuits are presented
here,but this time a new circuit using a thermistor and a timer to do
the trick. The circuit is as simple and straight forward so that, it
can be easily implemented. The thermistor offers a low resistance at
high temperature and high resistance at low temperature. This
phenomenon is employed here for sensing the fire.
here,but this time a new circuit using a thermistor and a timer to do
the trick. The circuit is as simple and straight forward so that, it
can be easily implemented. The thermistor offers a low resistance at
high temperature and high resistance at low temperature. This
phenomenon is employed here for sensing the fire.
The
IC1 (NE555) is configured as a free running oscillator at audio
frequency. The transistors T1 and T2 drive IC1. The output (pin 3) of
IC1 is couples to base of transistor T3 (SL100), which drives the
speaker to generate alarm sound. The frequency of NE555 depends on the
values of resistances R5 and R6 and capacitance C2. When thermistor
becomes hot, it gives a low-resistance path for the positive voltage to
the base of transistor T1 through diode D1 and resistance R2.
Capacitor C1 charges up to the positive supply voltage and increases
the the time for which the alarm is ON. The larger the value of C1, the
larger the positive bias applied to the base of transistor T1 (BC548).
As the collector of T1 is coupled to the base of transistor T2, the
transistor T2 provides a positive voltage to pin 4 (reset) of IC1
(NE555). Resistor R4 is selected s0 that NE555 keeps inactive in the
absence of the positive voltage. Diode D1 stops discharging of
capacitor C1 when the thermistor is in connection with the positive
supply voltage cools out and provides a high resistance path. It also
inhibits the forward biasing of transistor T1.
Circuit diagram with Parts list. IC1 (NE555) is configured as a free running oscillator at audio
frequency. The transistors T1 and T2 drive IC1. The output (pin 3) of
IC1 is couples to base of transistor T3 (SL100), which drives the
speaker to generate alarm sound. The frequency of NE555 depends on the
values of resistances R5 and R6 and capacitance C2. When thermistor
becomes hot, it gives a low-resistance path for the positive voltage to
the base of transistor T1 through diode D1 and resistance R2.
Capacitor C1 charges up to the positive supply voltage and increases
the the time for which the alarm is ON. The larger the value of C1, the
larger the positive bias applied to the base of transistor T1 (BC548).
As the collector of T1 is coupled to the base of transistor T2, the
transistor T2 provides a positive voltage to pin 4 (reset) of IC1
(NE555). Resistor R4 is selected s0 that NE555 keeps inactive in the
absence of the positive voltage. Diode D1 stops discharging of
capacitor C1 when the thermistor is in connection with the positive
supply voltage cools out and provides a high resistance path. It also
inhibits the forward biasing of transistor T1.
Notes.
- The circuit can be powered from a 6V battery or a 6V power supply.
- Click Here ! for the circuit diagram of a power supply circuit for this project.
- The thermistor can be mounted on a heat resistant material like mica to prevent it from damage due to excessive heat.
- The LED acts as an indication when the power supply is switched ON.
Tuesday, April 9, 2013
FM transmitter using UPC1651
Here is the circuit diagram of an FM
transmitter using the IC UPC1651. UPC1651 is a wide band UHF Silicon
MMIC amplifier. The IC has a broad frequency response to 1200MHz and
power gain up to 19dB.The IC can be operated from 5V DC.
The audio
signals picked by the microphone are fed to the input pin (pin2) of the
IC via capacitor C1. C1 acts as a noise filter. The modulated FM
signal will be available at the output pin (pin4) of the IC. Inductor
L1 and capacitor C3 forms the necessary LC circuit for creating the
oscillations. Frequency of the transmitter can be varied by adjusting
the capacitor C3.Circuit diagram with Parts list.
Notes.
Continue reading...
transmitter using the IC UPC1651. UPC1651 is a wide band UHF Silicon
MMIC amplifier. The IC has a broad frequency response to 1200MHz and
power gain up to 19dB.The IC can be operated from 5V DC.
The audio
signals picked by the microphone are fed to the input pin (pin2) of the
IC via capacitor C1. C1 acts as a noise filter. The modulated FM
signal will be available at the output pin (pin4) of the IC. Inductor
L1 and capacitor C3 forms the necessary LC circuit for creating the
oscillations. Frequency of the transmitter can be varied by adjusting
the capacitor C3.Circuit diagram with Parts list.
Notes.
- The circuit can be assembled on a Vero board.
- Inductor L1 can be made by making 5 turns of 26SWG enameled copper wire on a 4mm diameter plastic former.
- A ¾ meter insulated copper wire can be used as the antenna.
- Do not give more than 6V to the IC.
- Mic M1 can be a condenser microphone.
Thursday, April 4, 2013
Reducing L200 Power Dissipation Circuit using Series Resistor
It’s good to reduce the power dissipated by the device. Using resistor connected in series to the input (the left figure) is a simple and economic method to reduce the device input-output differential voltage. This is the figure of the design circuit;
Here’s the formula for calculating R:
R= [Vi min- (Vo+Vdrop)]/Io
Vdrop = minimum differential voltage between the input and the output of the device at current Io
Vin min = minimum voltage
Vo = Output voltage
Io = output current
Resistor R can be connected between pins 1 and 2 of the IC instead of in series with the input if the load is constant (the right figure). So, part of the load current flows through the device and part through the resistor. This configuration is available when the minimum current by the load is:
Io min = Vdrop/R
Sunday, March 24, 2013
Fire Alarm Using Thermistor
Small and simple unit, Can be used for Home-Security purpose
In this fire alarm circuit, a Thermistor works as the heat sensor. When temperature increases, its resistance decreases, and vice versa. At normal temperature, the resistance of the Thermistor (TH1) is approximately 10 kilo-ohms, which reduces to a few ohms as the temperature increases beyond 100 C. The circuit uses readily available components and can be easily constructed on any general-purpose PCB.
Circuit Diagram:
Fire Alarm Using Thermistor Circuit Diagram| Parts | Description |
| R1 | 470R |
| R2 | 470R |
| R3 | 33K |
| R4 | 560R |
| R5 | 470R |
| R6 | 47K |
| R7 | 2.2K |
| R8 | 470R |
| C1 | 10uF-16V |
| C2 | 0.04uF-63V |
| C3 | 0.01uF-63V |
| Q1 | BC548 |
| Q2 | BC558 |
| Q3 | SL100B |
| D1 | Red Led |
| D2 | 1N4001 |
| IC1 | NE555 |
| SPKR | 1W-8R |
| TH1 | Thermistor-10K |
Timer IC NE555 (IC1) is wired as an astable multivibrator oscillating in audio frequency band. Switching transistors Q1 and Q2 drive multivibrator IC1. The output of IC1 is connected to NPN transistor Q3, which drives the loudspeaker (SPKR) to generate sound. The frequency of IC1 depends on the values of resistors R6, R7 and capacitor C2. When Thermistor TH1 becomes hot, it provides a low-resistance path to extend positive voltage to the base of transistor Q1 via diode D2 and resistor R3. Capacitor C1 charges up to the positive voltage and increases the ‘on’ time of alarm. The higher the value of capacitor C1, the higher the forward voltage applied to the base of transistor Q1. Since the collector of transistor Q1 is connected to the base of transistor Q2, transistor Q2 provides positive voltage to reset pin 4 of IC1. R5 is used such that IC1 remains inactive in the absence of positive voltage. D2 stops discharging of capacitor C1 when the Thermistor connected to the positive supply cools down and provides a high-resistance (10k) path. It also stops the conduction of Q1. To prevent the Thermistor from melting, wrap it up in mica tape. The circuit works off a 6V-12V regulated power supply. D1 is used to indicate that power to the circuit is switched on.
Water Level Indicator Using 7 Segment Display
This water-level indicator uses a 7-segment display, instead of LEDs, to indicate the water level (low, half and full) in the tank. Moreover, a buzzer is used to alert you of water overflowing from the tank. The circuit shows the water level by displaying L, H and F for low, half and full, respectively. The circuit uses five sensors to sense the different water levels in the tank. Sensor A is connected to the negative terminal (GND) of the power supply. The other four sensors (B through E) are connected to the inputs of NOT gate IC 7404. When there is a high voltage at the input pin of the NOT gate, it outputs a low voltage. Similarly, for a low voltage at the input pin of the NOT gate, it outputs a high voltage.
When the tank is empty, the input pins of IC 7404 are pulled high via a 1-mega-ohm resistor. So it outputs a low voltage. As water starts filling the tank, a low voltage is available at the input pins of the gate and it outputs a high voltage. When the water in the tank rises to touch the low level, there is a low voltage at input pin 5 of gate N3 and high output at pin 6. Pin 6 of the gate is connected to pin 10 of gate N9, so pin 10 also goes high. Now as both pins 9 and 10 of gate N9 are high, its output pin 8 also goes high. As a result, positive supply is applied to DIS3 and it shows ‘L’ indicating low level of water in the tank. Similarly, when water in the tank touches the half level, pins 4 and 5 of AND gate N8 become high.
As a result, its output also goes high and DIS2 shows ‘H’ indicating half level of water in the tank. At this time, pin 9 of gate N9 also goes low via gate N4 and DIS3 stops glowing. When the water tank becomes full, the voltage at pin 1 of gate N1 and pin 3 of gate N2 goes low. Output pin 3 of gate N7 goes high and DIS1 shows ‘F’ indicating that the water tank is full. When water starts overflowing the tank, pin 13 of gate N6 goes low to make output pin 12. The buzzer sounds to indicate that water is overflowing the tank and you need to switch off the motor pump. Assemble the circuit on a general-purpose PCB and enclose in a suitable box. Use a non-corrosive material such as steel strip for the five sensors and hang them in the water tank as shown in the circuit diagram. Use regulated 5V to power the circuit.
Continue reading...
When the tank is empty, the input pins of IC 7404 are pulled high via a 1-mega-ohm resistor. So it outputs a low voltage. As water starts filling the tank, a low voltage is available at the input pins of the gate and it outputs a high voltage. When the water in the tank rises to touch the low level, there is a low voltage at input pin 5 of gate N3 and high output at pin 6. Pin 6 of the gate is connected to pin 10 of gate N9, so pin 10 also goes high. Now as both pins 9 and 10 of gate N9 are high, its output pin 8 also goes high. As a result, positive supply is applied to DIS3 and it shows ‘L’ indicating low level of water in the tank. Similarly, when water in the tank touches the half level, pins 4 and 5 of AND gate N8 become high.
As a result, its output also goes high and DIS2 shows ‘H’ indicating half level of water in the tank. At this time, pin 9 of gate N9 also goes low via gate N4 and DIS3 stops glowing. When the water tank becomes full, the voltage at pin 1 of gate N1 and pin 3 of gate N2 goes low. Output pin 3 of gate N7 goes high and DIS1 shows ‘F’ indicating that the water tank is full. When water starts overflowing the tank, pin 13 of gate N6 goes low to make output pin 12. The buzzer sounds to indicate that water is overflowing the tank and you need to switch off the motor pump. Assemble the circuit on a general-purpose PCB and enclose in a suitable box. Use a non-corrosive material such as steel strip for the five sensors and hang them in the water tank as shown in the circuit diagram. Use regulated 5V to power the circuit.Friday, March 22, 2013
Making a 40 Watt LED Emergency Tubelight Circuit Using 1 Watt 350 mA LEDs
The article explains a simple yet effective 40 watt LED emergency tube light circuit which can be installed at home for acquiring uninterruptible illumination at the same time saving a lot of electricity and money.
You might have reads one of my earlier articles which explained a 40 watt LED street light system. The power saving concept is pretty much the same, through a PWM circuit, however the alignment of the LEDs has been laid in a completely different manner here.
As the name suggest the present idea is of an LED tube light and therefore the LEds have been configured in a straight horizontal pattern for better and efficient light distribution.
The circuit also features an optional emergency battery back up system which may be employed for getting an uninterruptible illumination from the LEDs even during the absence of normal mains AC. Due to the PWM circuit the acquired backup can extend up to more than 25 hours on every single recharge of the battery (rated at 12V/25AH).
The PCB would be strictly needed for assembling the LEDs. The PCB must be an aluminum-back type. The track layout is shown in the below given picture. As can be seen the LEDs are spaced at a distance of about 2.5 cm or 25mm from each other for enhancing maximum and optimal distribution of light.
Either the LEDs may be laid over a single row or over a couple of rows.
A single row pattern is shown in the below given layout, due to lack of space only two series/parallel connection has been accommodated, the pattern is continued further on the right side of the PCB so that all the 40 LEDs become included.
Normally the proposed 40 watt LED tube light circuit, or in other words the PWM circuit may be powered through any standard 12V/3amp SMPS unit for the sake of compactness and decent looks.
After assembling the above board, the output wires should be connected to the below shown PWM circuit, across the transistor collector and positive. The supply voltage should be provided from any standard SMPS adapter as mentioned in the above section of the article. The LED trip will instantly light up illuminating the premise with flood light brightness. The illumination may be assumed to be equivalent to a 40 watt FTL with power consumption of less than 12 watts, thats a lot of power saved.
Emergency Battery Operation
If an emergency backup is preferred for the above circuit, it may be simply done by adding the following circuit.
Lets try to understand the design in more details:
The circuit shown above is the PWM controlled 40 watt LED lamp circuit, the circuit has been elaborately explained in this article. You can refer it for knowing more about its circuit functioning.
The next figure shown below is an automatic under voltage and over voltage battery charger circuit with automatic relay changeovers. The whole functioning may be understood with the following points:
The IC 741 has been configured as a low/high battery voltage sensor and it activates the adjoining relay connected to the transistor BC547 appropriately.
Assume the mains to be present and the battery to be partially discharged. The voltage from the AC/DC SMPS reaches the battery through the N/C contacts of the upper relay which remains in an deactivated position because of the battery voltage which may be below the full charge threshold level, lets assume the full charge level to be 14.3V (set by the 10K preset).
Since the lower relay coil is connected to the SMPS voltage, stays activated such that the SMPS supply reaches the PWM 40 watt LED driver via the N/O contacts of the lower relay.
Thus the LEDs remains switched ON by using the DC from the mains operated SMPS adapter, also the battery continues to get charged as explained above.
Once the battery gets fully charged, the output of the IC741 goes high, activating the relay driver stage, the upper relay switches and instantly connects the battery with the N/C of the lower relay, positioning the battery in the standby condition.
However until AC mains is present, the lower relay is unable to deactivate and therefore the above voltage from the charged battery is not able to reach the LED board.
Now if suppose AC mains fails, the lower relay contact shifts to the N/C point, instantly connects the supply from the battery to the PWM LED circuit, illuminating the 40 watt LEDs brightly.
The LEDs consume battery power until either the battery falls below the low voltage threshold or mains power is restored.
The low battery threshold setting is done by adjusting the feedback preset 100K across the pin3 and pin6 of the IC741.
You might have reads one of my earlier articles which explained a 40 watt LED street light system. The power saving concept is pretty much the same, through a PWM circuit, however the alignment of the LEDs has been laid in a completely different manner here.
As the name suggest the present idea is of an LED tube light and therefore the LEds have been configured in a straight horizontal pattern for better and efficient light distribution.
The circuit also features an optional emergency battery back up system which may be employed for getting an uninterruptible illumination from the LEDs even during the absence of normal mains AC. Due to the PWM circuit the acquired backup can extend up to more than 25 hours on every single recharge of the battery (rated at 12V/25AH).
The PCB would be strictly needed for assembling the LEDs. The PCB must be an aluminum-back type. The track layout is shown in the below given picture. As can be seen the LEDs are spaced at a distance of about 2.5 cm or 25mm from each other for enhancing maximum and optimal distribution of light.
Either the LEDs may be laid over a single row or over a couple of rows.
A single row pattern is shown in the below given layout, due to lack of space only two series/parallel connection has been accommodated, the pattern is continued further on the right side of the PCB so that all the 40 LEDs become included.
Normally the proposed 40 watt LED tube light circuit, or in other words the PWM circuit may be powered through any standard 12V/3amp SMPS unit for the sake of compactness and decent looks.
After assembling the above board, the output wires should be connected to the below shown PWM circuit, across the transistor collector and positive. The supply voltage should be provided from any standard SMPS adapter as mentioned in the above section of the article. The LED trip will instantly light up illuminating the premise with flood light brightness. The illumination may be assumed to be equivalent to a 40 watt FTL with power consumption of less than 12 watts, thats a lot of power saved.
Emergency Battery Operation
If an emergency backup is preferred for the above circuit, it may be simply done by adding the following circuit.
Lets try to understand the design in more details:
The circuit shown above is the PWM controlled 40 watt LED lamp circuit, the circuit has been elaborately explained in this article. You can refer it for knowing more about its circuit functioning.
The next figure shown below is an automatic under voltage and over voltage battery charger circuit with automatic relay changeovers. The whole functioning may be understood with the following points:
Assume the mains to be present and the battery to be partially discharged. The voltage from the AC/DC SMPS reaches the battery through the N/C contacts of the upper relay which remains in an deactivated position because of the battery voltage which may be below the full charge threshold level, lets assume the full charge level to be 14.3V (set by the 10K preset).
Since the lower relay coil is connected to the SMPS voltage, stays activated such that the SMPS supply reaches the PWM 40 watt LED driver via the N/O contacts of the lower relay.
Thus the LEDs remains switched ON by using the DC from the mains operated SMPS adapter, also the battery continues to get charged as explained above.
Once the battery gets fully charged, the output of the IC741 goes high, activating the relay driver stage, the upper relay switches and instantly connects the battery with the N/C of the lower relay, positioning the battery in the standby condition.
However until AC mains is present, the lower relay is unable to deactivate and therefore the above voltage from the charged battery is not able to reach the LED board.
Now if suppose AC mains fails, the lower relay contact shifts to the N/C point, instantly connects the supply from the battery to the PWM LED circuit, illuminating the 40 watt LEDs brightly.
The LEDs consume battery power until either the battery falls below the low voltage threshold or mains power is restored.
The low battery threshold setting is done by adjusting the feedback preset 100K across the pin3 and pin6 of the IC741.
Wednesday, March 20, 2013
Voltage Inverter Using Switch Mode Regulator
This circuit uses a step-up switch-mode regulator, which is usually used to produce a positive supply, to generate a regulated negative output voltage. The device used here is the MIC4680 from Micrel (www.micrel.com), but the idea would of course work with similar regulators from other manufacturers. Because of coil L1, which performs the voltage conversion by the intermediate storage of energy in the form of a magnetic field, the output is effectively isolated from the input. We can therefore connect the right-hand side of L1 to ground rather than to the positive output without causing a large current to flow. Then we connect the ground pin of the regulator IC and all the components connected to it as the negative voltage output, isolated from ground.
The components on the output side of the regulator are connected as usual: flywheel diode D1, coil L1 and the voltage divider formed by R1 and R2. These last two components set the output voltage, according to a formula given in the data sheet. Example component values for the MIC4680 used here are given in the table. The input voltage should lie within the permitted range for the regulator used, and must in any case be at least as great in magnitude as the desired output voltage (here +5 V or +12 V), so that the step-down regulation technique can wor.
It is important to take care when building this circuit to mount the regulator using an insulator, since generally the GND pin of the device is connected to the heatsink tab. Also, the ON/OFF control input cannot be driven using a normal logic signal, since the regulator’s ground reference is the output voltage rather than ground itself. If the ON/OFF function is required, a level shifter or optocoupler must be used.
Source: http://www.ecircuitslab.com/2011/06/voltage-inverter-using-switch-mode.html
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