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# HarryA

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## Posts posted by HarryA

2. ### Help identifying electronic components

Yes, you are not the only one with that problem! See the circuit here:

I was thinking you could get the correct parts from that one but no such good luck.

3. ### Help identifying electronic components

The eight leaded DIP is a " Low power offline switched-mode power supply primary switcher" see:

The larger diode P6? maybe a protection diode to protect from over-voltage. The  two smaller diodes most likely  are rectifiers used as part of the power supply. The question is what caused the fault that damaged the components.

You need to investigate that before replacing the components else they may just blowout again.

Try drawing out that part of the circuit to get insight into the circuit.

4. ### BCD calculator (urgent help in project)

There is an article "Design Project2 - BCD Calculator" that maybe helpful.

5. ### Repairing my Studio Microphones

Hunter College has a course in electronics that is  online. That maybe helpful:
Lessons are ElectronicsLab1.pdf through ElectronicsLab15.pdf

"Practical Electronics for Inventors" by Scherz and Monk is a very  good book by not cheap.

6. ### Half Bridge Driver IR2153

The good news with the IR2153 is that it has a 50% duty cycle. The bad news is that you can not change it like in the 555 timer.

You can change the frequency which would change the impedance at the coil/transformer which may give you some control of the output with the potentiometer PR1. Perhaps a larger potentiometer?

Others may find the two schematics here easier to follow - without all the bells and whistles of this one.

7. ### Boolean Algebra

from Wikipedia:

= (K+L)(K+M)(L+N)(M+P)(N+Q)(P+Q)
= (K+LM)(N+LQ)(P+MQ)
= (KN+KLQ+LMN+LMQ)(P+MQ)
= KNP + KLPQ + LMNP + LMPQ + KMNQ + KLMQ + LMNQ + LMQ

-----------------------------------------------------------------------------------------

K * N+LQ   +  LM*(N+LQ)

K * N+LQ = KN+KLQ    and LM*(N+LQ) =  LMN+LMQ

for the : (KN+KLQ+LMN+LMQ)

for the fourth line multiply the third line  by P and then by MQ from (P+MQ)

8. ### Snubber Circuit Design 230V, 16A, Problem in small load, Current Flow!

The capacitance reactance of the 100nf would be in the order of 26.6K so that could give you a current in the order of a few milli-amperes.

The leakage current of the varistor is less than 20 micro-amperes for the 7D471K.

9. ### Timed actuator

You can get timers that will go down to 1 second that maybe helpful. For example:
"7-Day Programmable, Minimum Setting Time is 1 Second "

You can also get 110 volt solenoids that would work off the timer. For example.

If you need a dc solenoid you can get a small power supply that works with the timer. For example.

And 12 volt solenoids are readily available:

There are 12 volt solenoids that are designed for door latches if that is helpful.

For the solenoids:  4.5N (newtons) equals 1 pound of force.

10. ### Any software tools to make double-sided circuit boards?

Perhaps you may find something useful here:

11. ### Anyone knows this component?

Most likely it is the manufacturer's part number.  Perhaps you can find a schematic diagram?

12. ### Voltage drop: Circuit to control fans and leds

When the switch is closed in the debouncing circuit the input to the inverter is a logic 0 and the output a logic 1.

Current flows from the battery supply of the inverter to its output. But the absolute maximum current rating for the output of a 74HC14 is only 24 ma.

Do you really need a debouncing circuit?    I wonder if you could replace the mosfet and debouncing circuuit with a 3 position switch;  An On-Off-On. If not you may need a transistor between the inverter and the load. But you get a lost of 0.5 or 0.7 volts.

Also the 100mfd capacitors are quite large for you circuit; charging the one through 2000 ohms will take awhile. Perhaps 1.0 mfd?

13. ### "period and duty cycle" - electronics lab"

If you search for Arduino function or signal generator you will find some useful information.  Like:

14. ### "period and duty cycle" - electronics lab"

The URL is:

The code has numinous errors. It would never run,

for spuddo:

This is a snapshot of the serial monitor displaying the output of the code below.

This is the circuit that I used. The duty control on the left. The two resistors limit the range of the output. You do not want zero duty cycle for example. The period control on the right. The resistor limits the period from going to zero for example.

The code:

```//
// A rework of the code from the video: https://www.youtube.com/watch?v=bIz9ektLunE
//
void virtual_Scope();
int iDutyCyclePin = 2; //set input pin for the left pot = duty cycle
int iPeriodPin    = 1; //set input pin for the right pot = peroid
int iLedPin = 13;   //ser pin for output to LED
//float fFrequency;   //frequency = how many full periods per second or per 1000 millisedonds
float fPeriod = 10;  //value from the left pot
float fDuty = 1;
long int liPeriod, liDuty;
int iDutyPercent;
long int liHigh_Time, liLow_Time;

void setup()
{
pinMode(iLedPin, OUTPUT); //declare ledpin as OUTPIN
//Serial Port begin
Serial.begin (9600);
}

void loop()
{
fPeriod = analogRead(iPeriodPin);   //read the value from  the right pot = period
fDuty = analogRead(iDutyCyclePin); //read the value from the left pot = duty cycle

//limit the range of the duty cycle to 20 to 80 percent of the period because that is what works!
fDuty = (fDuty*9/10000) * fPeriod ;  //with 5 volt supply
liDuty = int(fDuty);  //for printouts below
liPeriod = int(fPeriod);

//iDutyPercent = 100*liDuty/1024;     //cal duty cycle as percent for serial monitor  ????
iDutyPercent = 100*liDuty/liPeriod; //cal duty cycle as percent for serial monitor
//  fFrequency = (1000/float(liPeriod));  //cal frequency in units of Hertz for serial monitor ???

// liHigh_Time = liDuty*liPeriod/1024;   //cal high = on time   ???
liHigh_Time = liDuty;   // high = on time
liLow_Time = liPeriod - liHigh_Time; //cal low = off time

Serial.println();  //new line
Serial.print("period ");
Serial.print(liPeriod);
Serial.println("  milliseconds");

Serial.print("duty ");
Serial.print(liDuty);
Serial.println("  milliseconds");

Serial.print("on time ");
Serial.print(liHigh_Time);
Serial.println("  milliseconds");

Serial.print("off time ");
Serial.print(liLow_Time);
Serial.println("  milliseconds");

Serial.print(" duty cycle ");
Serial.print(iDutyPercent);
Serial.println(" % ");

//  Serial.print("frequency ");  //what is frequency here?
//  Serial.print(fFrequency);
//  Serial.println(" Hertz");

digitalWrite(iLedPin, HIGH);   //set the ledPin on
delay(liHigh_Time);           //pause the program for  high_time in microseconds

digitalWrite(iLedPin, LOW);   //set the ledPin off
delay(liLow_Time);           //pause the program for  low_time in microseconds

virtual_Scope();             //display trace

delay(4000);                //slow down the scrolling
}
void virtual_Scope()
{
//display a line of pulses

int iHighDashes, iLowDashes;
int iCount;

//let one dash = 30 ms
iHighDashes = liHigh_Time/30;
iLowDashes = liLow_Time/30;

iCount = 60/(iHighDashes+iLowDashes); //try to make the lengths similar

// Serial.println(String(iCount) + "  "+ String(iLowDashes) + "  " + String(iHighDashes) ); //new line for space at top
Serial.println(); //space at top

while (iCount--)
{
for (int i=0; i <iLowDashes; i++)
{
Serial.print("_");
}
for (int i=0; i <iHighDashes; i++)
{
Serial.print("-");
}
}
Serial.println(); //space at bottom
}```

15. ### "period and duty cycle" - electronics lab"

Given what he shows in the video one can emulate  the code easily. If that is what you would like.

16. ### BB-e01p

I gather  one would need a microcomputer to interface one with the other.  I take it  the output one is not compatible with the input of the other?

17. ### scroll a single line lcd arduino

or cleaner:

```String DisplayString = " "; //a blank string
int percent1 = 0;
int OldPercent = 0;

void setup()
{
//   Serial.begin(9600); //testing
}
void loop()
{
if( OldPercent != percent1 ) //do not scroll needlessly
{
//previous string - set the cursor to second line
LCD.setCursor(0,2);
LCD.print(DisplayString); //move previous line down

//set the cursor to for new first line
LCD.setCursor(0,1);

if (percent1 > 50)
{
//new string
DisplayString = "Moisture S1 : " + String(percent1) + "%" + " Irrigaion sistem ON";
}

else
{
//new string
DisplayString = "Moisture S1 : " + String(percent1) + "%" + " Irrigaion sistem OFF";
}
//set the cursor for new first line
LCD.setCursor(0,1);

LCD.print(DisplayString); //new line to top of the LCD
OldPercent = percent1;  //set new percent
}

} //end  loop```

the first "set the cursor for new first line" code  is redundant; I can not see how to edit the code

18. ### scroll a single line lcd arduino

Perhaps:

```String DisplayString = " "; //a blank string
int percent1 = 0;
int OldPercent = 0;

void setup()
{
//   Serial.begin(9600); //testing
}
void loop()
{
if( OldPercent != percent1 ) //do not scroll needlessly
{
//previous string - set the cursor to second line
LCD.setCursor(0,2);
LCD.print(DisplayString); //moves previous line down

if (percent1 > 50)
{

//new string
DisplayString = "Moisture S1 : " + String(percent1) + "%" + " Irrigaion sistem ON";

//set the cursor to for new first line
LCD.setCursor(0,1);
LCD.print(DisplayString); //new line to top of the LCD

OldPercent = percent1;  //set new percent
}

else
{
//new string
DisplayString = "Moisture S1 : " + String(percent1) + "%" + " Irrigaion sistem OFF";

//set the cursor to new first line
LCD.setCursor(0,1);
LCD.print(DisplayString); //new line to top of the LCD

OldPercent = percent1;  //set new percent
}
}

} //end  loop```

19. ### Lobstamon

"Could a capacitor smooth the frequency? "

If one does not know what is  wrong with the system then one can not know what the affects of a capacitor would be.

1. you have a 12 5kw diesel generator
2. the generator outputs 120 or 240 volts at 50 or 60 hertz.
3. the generator supplies the mains that has numerous outlets on the boat.
4.  the generator output is stable until you turn on the ac unit.
5. with the ac running the voltage  at the various outputs are no longer 50 or 60 hertz but varying in frequency

Is that correct?

20. ### Transistor Substitute.

48 volts is above the absolute voltage for this voltage regulator: 35 volts maximum:

21. ### Lobstamon

In that  type of air conditioner the input ac voltage is converted into dc via a power supply. The dc voltage is converted (inverted) into  variable frequency ac.

The frequency depends on the demand on the unit. A microcontroller  samples the ambient air temperature and adjusts  the speed of the compressor motor via the  frequency of the ac applied to the compressor motor.

Invert versus convert is interesting:

• Inverter  - dc to ac
• converter - ac to ac  (transformer, etc)
• converter - dc to dc  (potentiometer, etc)
• power supply - ac to dc
22. ### Transient Suppression MOV Selection?

I have not used varistors but not letting ignorance slow me down. The V20E14AUTO  is a 16 volt MOV.

Voltage Rating DC: 16vdc
Varistor Voltage:  22 volts this is where the varistor starts to conduct at 1 ma. Varistors draw some small current always
Clamping Voltage:  43 volts the voltage any spike is truncated to.
Peak Surge Current: 20 amperes.
Surge Energy Rating: 28 joules.  28 watts-1 second, 56 watts-500 ms, etc

Unlike Zener diodes that fail as an open circuit varistors fail as a short circuit so in some cases a fuse
is used with them. Most likely on the larger ones..
see:

or:

That is my best guess; perhaps someone else has experience with varistors?

"The MagLock Draws 420mA 2 12 Volts, The panels power supply provides 500mA @ 14.3 V "

Do you need to reduce the 14.3 volts to 12 volts?

23. ### Introduction to Non-Inverting and Inverting Amplifiers Basics

Wikipedia has a well written article on operational amplifier applications.

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