Showing posts with label on. Show all posts
Showing posts with label on. Show all posts
Tuesday, November 4, 2014
Stereo Power Amplifier Circuit based on BA5417
BA5417 is a stereo amplifier IC with a lot of good features like thermal shut down, standby function, soft clipping, wide operating voltage range etc. The IC can deliver 5W per channel into 4 ohm loud speakers at 12V DC supply voltage. The BA5417 has excellent sound quality and low THD (total harmonic distortion) around 0.1% at F=1kHz; Pout=0.5W.
Stereo Power Amplifier Circuit diagram :
Setup and working of this stereo power amplifier circuit is somewhat similar to the BA5406 based stereo amplifier circuit published previously. C10 and C11 are DC decoupling capacitors which block any DC level present in the input signals. C2 and C6 couples the amplifiers left and right power outputs to the corresponding loud speakers. C1 and C5 are bootstrap capacitors.
Bootstrapping is a method in which a portion of the amplifiers is taken and applied to the input. The prime objective of bootstrapping is to improve the input impedance. Networks R1,C3 and R2,C7 are meant for improving the high frequency stability of the circuit. C4 is the power supply filter capacitor. S1 is the standby switch. C8 is a filter capacitor. R3 and R4 sets the gain of the left and right channels of the amplifier in conjunction with the 39K internal feedback resistors.
Note :
- Supply voltage range of BA5417 is from 6 to 15V DC.
- The recommended supply voltage for this circuit is 12V DC.
- The power supply must be well regulated and filtered.
- BA5417 requires a heatsink.
- The circuit can be assembled on a perf board without much degradation in performance.
Monday, October 20, 2014
On Demand WC Fan Using 555
In most WCs with an extractor the fan is connected to the lighting circuit and is switched on and off either in sympathy with the light or with a short delay. Since toilets are sometimes used for washing the hands or just for a quick look in the mirror, it is not always necessary to change the air in the smallest room in the house. The following circuit automatically determines whether there really is any need to run the fan and reacts appropriately. No odour sensor is needed: we just employ a small contact that detects when and for how long the toilet seat lid is lifted.
On-Demand WC Fan Using 555 circuit diagram
If the seat lid is left up for at least some presettable minimum time t1, the fan is set running for another presettable time t2. In the example shown the contact is made using a small magnet on the lid and a reed switch mounted on the cistern. The rest is straightforward: IC2, the familiar 555, forms a timer whose period can be adjusted up to approximately 10 to 12 minutes using P2. This determines the fan running time. There are three CMOS NAND gates (type 4093) between the reed switch and the timer input which generate the required trigger signal. When the lid is in the ‘up’ position the reed switch is closed.
Capacitor C1 charges through P1 until it reaches the point where the output of IC1a switches from logic 1 to logic 0. The output of IC1b then goes to logic 1. The edge of the 0-1 transition, passed through the RC network formed by C2 and R2, results in the output of IC1c going to logic 0 for a second. This is taken to the trigger input on pin 2 of timer IC2, which in turn switches on the relay which causes the fan to run for the period of time determined by P2. The circuit is powered from a small transformer with a secondary winding delivering between approximately 8 V and 10 V. Do not forget to include a suitable fuse on the primary side.
The circuit around IC1b and IC1c ensures that the fan does not run continuously if the toilet seat lid is left up for an extended period. The time constant of P1 and C1 is set so that the fan does not run as a result of lavatorial transactions of a more minor nature, where the lid is opened and then closed shortly afterwards, before C1 has a chance to charge sufficiently to trigger the circuit.
Circuit Source: DIY Electronics Projects
Thursday, September 11, 2014
18W amplifier circuit based on IC HA13118
Here the 18W audio amplifier schema which powered by IC HA13118 as the main component.The type of this amplifier is bridge amplifier since the output line does not grounded.
The supply voltage required for this schema is 8 – 18V DC, at least 1 to 2 Amps. Maximum output power will only be obtained with a power supply of 18V at greater than 2 A, using a 4 ohm speaker. The power supply should be well filtered to reduce mains hum, a regulated supply will reduce noise even further. Extra filtering is unnecessary if operating from a battery supply.
View more explanation about this 18W audio amplifier schema HERE.
Sunday, September 7, 2014
100W MOSFET Power Amplifier based on IRFP240
Capacitor C8 is the input DC decoupling capacitor that blocks DC voltage if any from the input source. IF unblocked, this DC voltage can alter the bias setting s of the succeeding stages. Resistor R20 limits the input current to Q1 C7 bypasses any high frequency noise from the input. Transistor Q1 and Q2 forms the input differential combine and the constant current source circuit designed around Q9 and Q10 sources 1mA. Preset R1 is employed for adjusting the voltage at the output of the amplifier. Resistors R3 and R2 sets the gain of the amplifier. The second differential stage is created by transistors Q3 and Q6 whiles transistors q4 and Q5 forms a current mirror that makes the second differential combine to empty an identical current. this is worn out order to boost linearity and gain. Power amplification stage based on Q7 and Q8 that operates in thee category AB mode. Preset R8 will be used for adjusting the quiescent current of the amplifier. The network comprising of capacitor C3 and resistor R19 improves high frequency stability and prevents the possibility of oscillation. F1 and F2 are safety fuses.
Set R1 at midpoint before powering up and then change it slowly in order to induce a minimum voltage (less than 50mV0 at the output. Next step is fixing the quiescent current and keep the preset R8 in minimum resistance and connect a multimeter across points marked X & Y in the circuit diagram. currently change R8 so that the multimeter reads 16.5mV that corresponds to 50mA quiescent current.
Notes
- Assemble the circuit on a good quality PCB.
- Use a +45/-45 V DC, 3A dual supply for powering the circuit.
- Power supply voltage must not exceed +55/-55 V DC.
- Before connecting the speaker, check the zero signal output voltage of the amplifier and in any case it should not be higher than 50mV. If it is higher than 50mV, check the circuit for any error. Replacing Q1, Q2 with another set could also solve the problem.
- Fit Q7 and Q8 to a 2°C/W heat sink. Both Q7 and Q8 must be isolated from the heat sink using mica sheets. Heat sink mounting kits for almost all power transistors/ MOSFETs of almost all package styles are readily available in the market.
- All resistors other than R10, R11 and R19 are 1/4 watt metal film resistors. R10 and R11 are 5W wire wound type while R19 is a 3W wire wound type.
Wednesday, August 27, 2014
Power Audio Amplifier based on STK400xx
This is Power Audio Amplifier schema based on STK400xx series. Its will give you very good quality of sound this schema is unexpensive too since STK40xx series have low price. It is easy we make a power amplifier using only few external components. The STKxxxx amplifiers, for them we will find in enough eponymous stereo amplifiers , but also in enough activety loudspeakers. They do not need a lot of special knowledge of manufacture, only that attention in pins, in order to they do not break, and one good power supply.
Schematic Diagram:
Component Part list
STK40xx Series:
STK 4036 > Supply: ±35V - ±53,5V; Power (8R load): 50W
STK 4038 > Supply: ±40V - ±58V; Power (8R load): 60W
STK 4040 > Supply: ±43V - ±63V; Power (8R load): 70W
STK 4042 > Supply: ±46V - ±67V; Power (8R load): 80W
STK 4044 > Supply: ±51V - ±74V ; Power (8R load): 100V
Read More..
Schematic Diagram:
Component Part list
| R1-4 =1Kohm R2= 33Kohm R3-8=100ohm R5= 0.22ohm 5W R6=10ohm 2W R7= 6,8ohm 2W R9=12Kohm R10=10Kohm R11= 680ohm C1=560 pF 100V ceramic or mylar C2-7 =1 uF 63V MKT | C3-12 =220 uF 63V C4-5-10 =100 pF C6-9 =47uF 63V C8 =100 nF 100V MKT C11 =1 nF 100V MKT C13 =100 uF 25V C14=10pF 100V ceramic or mylar L1 =3μH [15 turns of 1mm around R6] 100V ceramic or mylar F1-2 =2A Fuse fast IC1=STK4036......STK4044 |
STK 4036 > Supply: ±35V - ±53,5V; Power (8R load): 50W
STK 4038 > Supply: ±40V - ±58V; Power (8R load): 60W
STK 4040 > Supply: ±43V - ±63V; Power (8R load): 70W
STK 4042 > Supply: ±46V - ±67V; Power (8R load): 80W
STK 4044 > Supply: ±51V - ±74V ; Power (8R load): 100V
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