21 Eylül 2010 Salı

Lead Acid Battery Charger #2

Lead Acid Battery Charger #2
The above pictured schematic diagram is just a standard constant current model with a added current limiter, consisting of Q1, R1, and R4. The moment too much current is flowing biases Q1 and drops the output voltage.

The output voltage is: 1.2 x (P1+R2+R3)/R3 volt. Current limiting kicks in when the current is about 0.6/R1 amp.
For a 6-volt battery which requires fast-charging, the charge voltage is 3 x 2.45 = 7.35 V. (3 cells at 2.45v per cell). So the total value for R2 + P1 is then about 585 ohm. For a 12 V battery the value for R2 + P1 is then about 1290 ohm.

For this power supply to work efficiently, the input voltage has to be a minimum of 3V higher than the output voltage.

P1 is a standard trimmer potentiometer of sufficient watt for your application.

The LM317 must be cooled on a sufficient (large) coolrib.

Q1 (BC140) can be replaced with a NTE128 or the older ECG128 (same company).

Except as a charger, this circuit can also be used as a regular power supply.

Parts List

Parts List:
R1 = 0.56 Ohm, 5W, WW
R2 = 470 Ohm C2 = 220nF
R3 = 120 Ohm
R4 = 100 Ohm
C1 = 1000uF/63V
Q1 = BC140
Q2 = LM317, Adj. Volt Reg.
C3 = 220nF (On large coolrib!)
P1 = 220 Ohm
 

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İzleyiciler

LED DİRENÇ HESAPLAMA

All LEDs require current limiting, without a current limiting mechanism the LED will usually burn out in under a second. Adding a simple resistor is the easiest way to limit the current. Use the calculator below to find out the value of resistor you require.

For example if you are wanting to power one of our_blank">red LEDs in an automotive application you would see that the typical forward voltage is 2.0 Volts and the maximum continuous forward current is 30mA. Therefore you would enter 14.5, 2.0 and 30 into the Single LED calculation box. After calculating you get 470ohm 1 watt as the result. Here is a that allows you to enter a resistor value and generate the corresponding color code.

Note: For automotive applications use the actual system voltage, not 12 Volts. Most 12 Volt system actually operate at around 14.5 Volts.

Supply Voltage
VOLTS
Voltage Drop Across LED
VOLTS
Desired LED Current
MILLIAMPS



Calculated Limiting Resistor
OHMS
Nearest higher rated 10% resistor

Calculated Resistor Wattage
WATTS
Safe pick is a resistor with
power rating of (common values are .25W, .5W, and 1W)
WATTS

LEDs in series

Several leds in series with one resistor
Supply Voltage
VOLTS
Voltage Drop Across LED
VOLTS
Desired LED Current
MILLIAMPS
How many LEDs connected




Calculated Limiting Resistor
OHMS
Nearest higher rated 10% resistor

Calculated Resistor Wattage
WATTS
Safe pick is a resistor with
power rating of (common values are .25W, .5W, and 1W)
WATTS
LM317 UYGULAMA DEVRELERİ HESAPLAMASI

 




Çıkış Voltajı
R1 resistor

R2 resistor

R1 resistor
R2 resistor

Çıkış Voltajı


Lm317 uygulama devreleri ve detayli bilgiye Buradan ulasabilirsiniz

LM555 - ASTABLE OSCILLATOR CALCULATOR

LM555 - ASTABLE OSCILLATOR CALCULATOR
Value Of R1 Ohms Value Of R2 Ohms
Value Of C1 Microfarads
Output Time HIGH SECONDS Output Time LOW SECONDS Output Period HIGH + LOW SECONDS Output Frequency HERTZ Output Duty Cycle PERCENT
Resistor values are in Ohms (1K = 1000) - Capacitor values are in Microfarads (1uF = 1)

NOTE: The leakage currents of electrolytic capacitors will affect the actual output results of the timers. To compensate for leakage it is often better to use a higher value capacitor and lower value resistances in the timer circuits.

LM555 Astable Oscillator Circuit Diagram


LM555 - ASTABLE CAPACITOR CALCULATOR

The next calculator can find the capacitance needed for a particular output frequency if the values of R1 and R2 are known.

Value Of R1 Ohms Value Of R2 Ohms
Frequency Desired Hertz
Capacitance uF
s

VOLT AMPER OHM ve WATT HESAPLAMA

Current:
kA (kiloamps) A (amps) mA (milliamps) µA (microamps)
Voltage:
kV (kilovolts) V (volts) mV (millivolts) µV (microvolts)