"I currently have a car stereo set that i use as an amplifier in my living room. but my main problem is that i a lot of noise hum when ever it is on especially when there happens to be a drop in the supply Voltage. i decided to use a voltage regulator and capacitor across (1600uF)...but it only reduced the hum a little. how can i completely eliminate the noise". - Question by FP
Answer by delabs
Ensure that the power supply has a full wave or bridge rectifier. If power supply transformer is say 12-0-12 two diodes must be there and a center tap ground OR If a square or round bridge is used with four leads or four diodes, then it is fine. Half wave rectification or a blown or leaky diode can cause this problem. Put all the filter caps you want and add a series choke as well the better the power supply the audio will be good.
The power supply transformer rating - voltage and current both may need to be boosted. Some very low budget transformers do not use CR-GO plates for lamination (i think it is Cold Rolled Grain Oriented ). They use plain thick metal plates without coating and hence hysteresis and eddy current both cause problems. Then you have ground loop hum and noise of semiconductors, the speaker ground and amplifier ground carry current and they should be directly connected to power supply ground, These you can understand by looking at these pages......
I am only aware of Phillips transistor based designs used 20 years back, but these have more...
"To solve the problem, the goal is to reduce the magnitude of the loop current. This is done simply by inserting isolation resistor(s) in series with the audio cable ground(s)..."
details required for... Atmels 89C52 Microcontroller A/D D/A converter Keypad LCD display(Or LED Display) 5V Regulated power supply. Temperature & Humidity controller using PID control algorithm implemented using Atmel's 89C52 microcontroller for a AHU unit ( Analog Input from the sensor(4 wire) 0-10v dc & Output from Microcontroller is 4-20mA to the Actuator through a DAC converter).
The Temperature & Humidity to be controlled are 24±1 degree Celsius and 55%±2% Rh respectively. provide me with good LINKS.
mail from SA
Get a sensor that gives a 0-10V or 4-20mA proportional to RH% and Temp deg C. what you need to do now is to select a A/D and a D/A for a real world interface
Build your own a laboratory instrument for measuring time and temperature. The DigiThermo demonstrates the use of 'C' language, a dual-slope converter, LCD interfacing, and digital filtering as well..
The Assembly language program for this may be the complex, due to PID. and my uC pages micro-delabs also in my other pages you can find theory on PID etc, in them i have MCS51 code for 2 setpoint process controller.
delabs
Other uC projects sites links
Temperature and Humidity Meter - This project is a combined temperature and humidity meter. It is an improvement on my PIC-based humidity meter and my PIC and AVR thermometers. I use an ATmega164, which as lots of I/O and memory.
Temperature and humidity measurements with the AVR web-server- The tuxgraphics Ethernet board has a lot of general purpose IO pins where external hardware such as sensors can easily be attached. In this example we use the sensirion sht11 sensor to measure temperature, humidity and calculate the dew point.
One thing tho, i would like to request you to send me some procedures on how to work with surface mount devices (SMD's). I cant get the IC as DIP so i have no choice but improvise an SMD. What is your most professional advice on this? Is it possible you could help me with any procedures for using an SMD on a PCB circuit?.
you may need a big tabletop magnifier with light and a fine tip soldering iron to get started. It may be difficult and needs a lot of practice, but many people are able to do it.
An SMT component is usually smaller than its through-hole counterpart because it has either smaller leads or no leads at all. It may have short pins or leads of various styles, flat contacts, a matrix of solder balls (BGAs), or terminations on the body of the component.
By Dean F. Poeth, II, Ph.D., P.E., C.Mfg.E.
For the Small Manufacturer and Hobbyist: Prototype Manufacturing, Rework, and Repair Techniques
SMDs have improved performance over through-hole components due to their smaller size, shorter internal leads, and smaller board layouts. These factors reduce the circuit’s parasitic inductance and capacitance. SMDs can also be more cost effective than traditional through-hole components due to the smaller board size, fewer board layers, and fewer holes.
What is Surface Mount Technology? Put Simply - It is a type of electronic component
package. Most electronic components can be divided into two categories - through hole (TH)
and surface mount (SM). Through-hole components have been used for many years and are
designed to be loaded on one side of a printed circuit board (PCB) and soldered on the other.
SM components are designed to be loaded and soldered on the same side of the PCB.
Luke Enriquez. Rev 1.3. August 2001.
VK3EM PO Box 98, Kerrimuir, Vic. 3129. Australia
One of the books here is The " Intersil Hot Ideas" - This was my Mentor Book These helped me build Intelligent Instruments in the 80s. Intersil( GE) was in advanced CMOS before anybody else. They made the smartest chips when the Microprocessors were being examined Skeptically by engineers. (At that time Microprocessors needed many support chips and consumed huge power only later CMOS uC came)
See also delabs Resources i have created as a reference for such doubts (2007)
i kinda found myself in a place where the voltage is so low (80v-110vAC) and i need to boost it up to 220v so what can i do? i have a burnt stabilizer (that is the electronics part) so i need the electronics circuit to replace the burnt one can Anybody help?
post by FP
here is a circuit i made for you, i am not sure it will work, i hope it will help you learn. part of these ideas are over 20 years old. Stabilizer Circuit
This circuit is a design i did, not tested by me as yet. It can Stabilize Mains voltage to around +/- 10% . It can be used for both 110V AC or 220V AC inputs with modifications. The Output is 220V AC. There is an overload, under voltage and over voltage trip circuit. With some tweaks and modifications it might work.
This circuit is a design concept, not tested by me and i did it just to explain some ideas. The circuit uses opto-coupler MOC3041 of Motorola and the Triac BTA-16-600 of ST as a solid state switch or relay. It also uses the LM324 quad opamp from National Semiconductor which is low power and single supply. As the MOC3041 switches the Triac at zero crossover there is no inter-winding short of transformer on crossover hopefully, the control circuit is designed in such a way that more than one triac will not be turned on at a time, i would like you to give feedback.
One more circuit, this is a bit complicated and it is not tested, it may not work that easy, just refer it to make your own design, it is just a bit of theory and my experience, i may be wrong at a few places.
