Skema rangkaian Battery Charge designed as a constant voltage source with a negative temperature coefficient. Transistor Q1 (BD 140) is used as the temperature sensor.
transistor Q2 is used to prevent the battery from discharging through
R1 when the mains power is not available. Rangkaian Battery Charge is
designed based on the voltage regulator IC LM350. The output voltage of
the charger can be adjusted between 13-15 V by varying the POT R6.
Download Skema :
Charge Battery Baterai 12 Volt
Passwor : asinan
Download Skema :
Charge Battery Baterai 12 Volt
Passwor : asinan
The
LM350 will try to keep the voltage drop between its input pin and the
output pin at a constant value of 1.25V. So there will be a constant current flow through the resistor R1. Q1 act here as a temperature sensor
with the help of components R6/R3/R4 which more or less control the
base current of Q1. As the emitter/base connection of transitor Q1, just
like any other semiconductor, contains a temperature coefficient of
-2mV/°C, the output voltage will also show a negative temperature
coefficient. That one is only a factor of 4 larger, because of the
variation of the emitter/basis of Q1 multiplied by the division factor
of P1/R3/R4. This results in approximately -8mV/°C. The LED will glow
whenever the mains power is available.
