Showing posts with label volt. Show all posts
Showing posts with label volt. Show all posts
Thursday, October 23, 2014
LM350 12 Volt Battery Charger
The battery circuit scheme is designed as a source of constant voltage with negative temperature coefficient. Transistor Q1 (BD 140) is used as a temperature sensor. transistor Q2 is used to prevent the battery from discharging through R1 when electrical power is unavailable. Charging circuit is designed based on the LM350 voltage regulator IC. The output voltage of the charger can be adjusted between 13-15 V by varying the POT R6.
LM350 will try to keep the voltage drop between the input pin and output pin at a constant value of 1.25V. So there will be a constant current flow through resistor R1. Q1 act here as a temperature sensor with the help of R6/R3/R4 components that are more or less controls the base current of Q1. As connection emitter / base of transistor Q1, the same as other semiconductors, containing the temperature coefficient of-2mV / ° C, the voltage output will also show a negative temperature coefficient. This one is just a factor of 4 large, because the variation of the emitter / base of Q1 is multiplied by a factor of division P1/R3/R4. This leads to some-8mV / ° C. LED will light whenever power is available.
Friday, October 17, 2014
1 5 volt dual LED flasher
This 1.5 volt led fasher runs more than a year on a single d" cell and alternately flashes 2 LEDs at about a 1 second rate. The circuit employs a 74HC14 CMOS hex inverter that will operate at very low voltages (less than 1 volt). One section is used as a squarewave oscillator (pins 1 and 2), while the others are wired to produce a short 10mS pulse on alternate edges of the square wave so the LEDs will alternate back and forth. The output sections each use a capacitor charge pump to increase the voltage for the LEDs. The circuit draws an average current of 800uA from the D battery and the LED peak current is about 40mA with a fresh battery and drops to about 10mA as the battery voltage falls to 1.1 volts. The capacity of a alkaline D cell is about 12 amp hours with a cutoff voltage of 1.1 so the circuit should run about 12/.0008 = 15000 hours or maybe 625 days, but I havent verified that yet. The idea for this circuit came from a single 1.5 volt LED flasher by Dave Johnson that can viewed at
Author : Bill Bowden
Sunday, October 5, 2014
10 Amp 13 8 Volt Power Supply
10 Amp 13.8 Volt Power Supply Circuit
10 Amp 13.8 Volt Power Supply Parts List :
R1 1.5K ¼ Watt Resistor (optional, tie pins 6 & 5 of IC1 together if not used.)
R2,R3 0.1 Ohm 10 Watt Resistor (Tech America 900-1002)
R4 270 Ohm ¼ Watt Resistor
R5 680 Ohm ¼ Watt Resistor
R6,R7 0.15 Ohm 10 Watt Resistor (Tech America 900-1006)
R8 2.7K ¼ Watt Resistor
R9 1K Trimmer Potentiometer (RS271-280)
R10 3.3K ¼ Watt Resistor
C1,C2,C3,C4 4700 Microfarad Electrolytic Capacitor 35 Volt (observe polarity)
C5 100 Picofarad Ceramic Disk Capacitor
C6 1000 Microfarad Electrolytic Capacitor 25 Volt (observe polarity)
IC1 LM723 (RS276-1740) Voltage Regulator IC. Socket is recommended.
Q1 TIP3055T (RS276-2020) NPN Transistor (TO-220 Heat Sink Required)
Q2,Q3 2N3055 (RS276-2041) NPN Transistor (Large TO-3 Heat Sink Required)
S1 Any SPST Toggle Switch
F1 3 Amp Fast Blow Fuse
D1-D4 Full Wave Bridge Rectifier (RS276-1185)
T1 18 Volt, 10 Amp Transformer Hammond #165S18 (Digi-Key HM538-ND)
Wednesday, September 3, 2014
TL496 3 to 9 volt converter Wiring diagram Schematic
This is simple Simple TL496 3 to 9 volt converter Circuit Diagram. it uses the TL496 power supply controller, a coil and a electrolytic capacitor. The maximum output voltage is actually 8.6V and current is around 80mA.The input current (the current drawn from the batteries) is 405mA at the maximum output current. Without load the current consumption is 125µA and the batteries life is around 166 days.
TL496 3 to 9 volt converter Circuit Diagram
Tuesday, August 19, 2014
1000 Volt DC to DC Regulator Circuit
Input voltage high voltage DC-DC converter 12V AC to 800 mA of current and then converted to DC through a rectifier diode 1A. The output voltage converter circuit can be adjusted in the range 0-1000V DC. This high voltage DC-DC converter uses the transformer as a base and several other active components include 555 timer IC, CMOS IC 4001, IC voltage regulator 7805, some NPN transistors and a pair of IRF510 MOSFET logic as a final amplifier.
The operation of the DC high voltage dc is the same principle as written in previous articles. The difference shown is this scheme is a converter output voltage high and can be arranged.
If a particular transformer mentioned in the scheme is not available, each AC transformer with 117V primary specification, 63V AC CT secondary to work. In this case, operating the converter circuit in a transformer sweet spot, you may need to select a frequency of unity.
The operation of the DC high voltage dc is the same principle as written in previous articles. The difference shown is this scheme is a converter output voltage high and can be arranged.
If a particular transformer mentioned in the scheme is not available, each AC transformer with 117V primary specification, 63V AC CT secondary to work. In this case, operating the converter circuit in a transformer sweet spot, you may need to select a frequency of unity.
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