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12V NiCAD Battery Charger

This is the circuit diagram of 12V NiCAD battery charger. The battery charger charging rate is at 200mA/Hour.



The battery charger circuit will continue to charge the battery at 75 mA until the battery is fully charged, then it reduces the current to a trickle rate. It will fully recharge a dead/unpowered battery in 4 hours and the battery can be left in the charger indefinitely. To set the shut off point, connect a 270 ohm / 2 Watt resistor across the charge terminals and adjust the potensiometer for 15.5V across the resistor.

Variable Power Supply Circuit 6-12V

The output voltage of this power supply circuit can be adjusted from 6 volt to 12 volt. The output voltage is regulated by Q1.


Parts List:

R1 = 470 ohm, 5%
R2 = 1K, 5%
P1 = 10K ohm Potentiometer
C1 = 1000uF/25V
T1 = 115[220]/8VAC transformer. Center Tap not needed.
Q1 = 2N1613, NTE128, or substitute. (TO-39 case) On coolrib!
BR1 = 40V, 4A. (Check max current of your mini-drill and add 2A)

Notes: C1 filters the noise and spikes off the AC. If you find the circuit output too noisy add another electrolytic capacitor over the output terminals. Value can be between 10 and 100uF/25V.10K-potentiometer used to adjust the output voltage.The transformer input voltage refer to your home power source.You may change the bridge diode with four rectifier diodes.

Battery Charger circuit for Lithium Battery

The following diagram is the circuit diagram of battery charger that can be used to re-charge your lithium batteries.
The charging with a constant current of 60 mA for AA batteries for a sequestration of 2.4 V per cell, when the charge should be terminated. The charging system is indicated for the battery to several cells of 2-6 cells connected series or series / parallel arrangements. It is important that all cells are assembled in the package is in the same state-of charge (voltage) before loading. upper cut-off voltage is 15.6 V (6 x 2.6 V). ICL7665 is a voltage monitor with dualover / under voltage detection.

Battery Charger circuit for Lithium Battery

0-24V Digital Variable Power Supply

The following circuit diagram is a variable power supply which controlled by PIC microcontroller. The LCD display is used to showing the actual value of output current voltage. This is a digital power supply, use the push on switch to adjust the output voltage and current value.
Schematic Diagram:

Visit the digital power supply circuit page for detail explanation

Logic Power Supply circuit with Overvoltage Protection

Here the simple 5V regulated power supply circuit which featured overvolatage protection.



The circuit work:
This circuit uses the crowbar method, where a thyristor is employed and short circuits the supply, causing the fuse to blow. This will take place in a few microseconds or less, and so offers much greater protection than an ordinary fuse. If the output voltage exceed 5.6Volt, then the zener diode will conduct, switching on the thyristor (all in a few microseconds), the output voltage is therefore reduced to 0 volts and sensitive logic IC's will be saved. The fuse will still take a few hundred milliseconds to blow but this is not important now because the supply to the circuit is already at zero volts and no damage can be done. The dc input to the regulator needs to be a few volts higher than the regulator voltage.

Read more circuit explanation at http://www.zen22142.zen.co.uk/Circuits/Power/overvolt.htm

Negative Adjustable Power Supply

This is a negative adjustable power supply. The power supply is regulated based on LM337T regulator IC. The LM337T is a regulator for negative voltage. This power supply output current is 1.5A max.

Schematic diagram:



Power Supply Input:


Component part list:
R1 = 330
R2 = 1K
VR1 = 10K 10-turn trimpot
C1 = 2200uF/50V
C2,4 = 100nF ceramic
C3,4 = 10uF/63V
D1-6 = 1N5403
REG IC = LM337T
Heatsink

This circuit is available in kit module at electronickits.com, you may buy the this power supply kit there. Here the manual of the kits which containing the schematic diagram, part list and the explanation of the power supply circuit.

Positive Adjustable Power Supply Circuit

Below is a positive regulated adjustable power supply based on LM317T regulator IC. The LM317T is a regulator for positive voltage. This power supply output current is 1.5A max.

Schematic diagram:



Power Supply Input:


Component part list:
R1 = 330
R2 = 1K
VR1 = 10K 10-turn trimpot
C1 = 2200uF/50V
C2,4 = 100nF ceramic
C3,4 = 10uF/63V
D1-6 = 1N5403
REG IC = LM317T
Heatsink

This circuit is available in kit module at electronickits.com. Here the manual of the kits which containing the schematic diagram, part list and the explanation of the power supply circuit.

6VDC to 12VDC Converter circuit

This is the circuit diagram of 6VDC to 12VDC Converter. With this circuit, you can doubled the input voltage of 6V DC to become 12V DC output voltage.


Component Parts:
R1, R4 = 2.2K
R2, R3 = 4.7K
R5 = 1K
R6 = 1.5K
R7 = 33K
R8 = 10K
C1,C2 = 0.1uFC3 = 470uF/25V
D1 = 1N914
D2 = 1N4004
D3 = 12V 400mW Zener Diode
Q1, Q2, Q4 = BC547
Q3 = BD679
L1 See Notes

Circuit Notes:
1. L1 is a custom inductor wound with about 80 turns of 0.5mm magnet wire around a toroidal core with a 40mm outside diameter.
2. Different values of D3 can be used to get different output voltages from about 0.6V to around 30V. Note that at higher voltages the circuit might not perform as well and may not produce as much current. You may also need to use a larger C3 for higher voltages and/or higher currents.
3. You can use a larger value for capacitor C3 to provide better filtering.
4. The circuit will require about 2A from the 6V supply to provide the full 800mA at 12V.

6VDC to 12VDV Converter circuit, source:
http://www.high-voltage-lab.com…

Batteries charger and PSU circuit

Here's a circuit diagram of the power supply and battery charger.




There are two parts in this circuit, ie the battery charger with a fixed output voltage, which is 5VDC. Another part is the regulated power supply that can be regulated output voltage between 2-9 volts.

source: http://www.electronics-lab.com

0-24VDC PIC Power Supply circuit

This is a digital variable power supply circuit which controlled using microcontroller chip PIC family.

Circuit Diagram:

For detailed information, visit this Digital PIC Power Supply circuit page

Adjustable Power Supply 6-12VDC

Here the another variable power supply which have adjustabled output voltage from 6-12 DC volt.Parts List:
T1 = 115[220]/8 VAC transformer.
Q1 = 2N1613, NTE128, or substitute. Use heatsink!
BR1 = 40V, 4A. (Check max current of your mini-drill and add 2A)
R1 = 470 ohm, 5%
R2 = 1K, 5%
P1 = potentiometer, 10K
C1 = 1000uF, 25VNotes: C1 filters the noise and spikes off the AC. If you find the circuit output too noisy add another electrolytic capacitor over the output terminals. Value can be between 10 and 100uF/25V.The output voltage is variable with the 10K-potentiometer.The transformer input voltage refer to your home power source.