Mutchus

This Mini Voltage Source with Adjustable Current Limit variable is very simple and efficient, ideal for small shippers or circuits that require a current limiter with adjustable voltage that this circuit can vary from a few mA up to 2 A and voltage 1.225v up to 12V or more, depending on the power supply.  Once the current reaches the limit set by the 100R resistor, transistor BC547 begins to act on the voltage regulator in the Adj pin and the output voltage starts to decrease. If the output is shorted, the output voltage will reduce to almost zero, as a kind of protection. Adjustable Voltage and Variable Current Limiter Circuit Diagram Adjustable Voltage and Variable Current Limiter Circuit Diagram

In electronics, a current divider is a simple linear circuit that produces an output current ( I X ) that is a fraction of its input current ( I T ). Current division refers to the splitting of current between the branches of the divider. The currents in the various branches of such a circuit will always divide in such a way as to minimize the total energy expended. The formula describing a current divider is similar in form to that for the voltage divider. However, the ratio describing current division places the impedance of the unconsidered branches in the numerator, unlike voltage division where the considered impedance is in the numerator. This is because in current dividers, total energy expended is minimized, resulting in currents that go through paths of least impedance, therefore the inverse relationship with impedance. On the other hand, voltage divider is used to satisfy Kirchoff's Voltage Law. The voltage around a loop must sum up to zero, so the voltage drops must be...

Description  In this circuit a LM339 quad voltage comparator is used to generate a time delay and control a high current output at low voltage. Approximatey 5 amps of current can be obtained using a couple fresh alkaline D batteries. Three of the comparators are wired in parallel to drive a medium power PNP transistor (2N2905 or similar) which in turn drives a high current NPN transistor (TIP35 or similar). The 4th comparator is used to generate a time delay after the normally closed switch is opened. Two resistors (36K and 62K) are used as a voltage divider which applies about two-thirds of the battery voltage to the (+) comparator input, or about 2 volts. The delay time after the switch is opened will be around one time constant using a 50uF capacitor and 100K variable resistor, or about (50u * 100K) = 5 seconds. The time can be reduced by adjusting the resistor to a lower value or using a smaller capacitor. Longer times can be obtained with a larger resistor or capacitor. To ope...

There are many ways of battery charging but constant-current charging, in particular,  is a popular method for lead-acid and Ni-Cd batteries. In this circuit, the battery  is charged with a constant current that is generally  one-tenth of the  battery capacity in ampere-hours. So for a 4.5Ah battery, constant charging current would be 450 mA. Circuit diagram : Constant Current Battery Charger Circuit Diagram This battery charger has the following features: It can charge 6V, 9V and 12V bat-teries. Batteries rated at other voltages can be charged by changing the values of zener diodes ZD1 and ZD2. Constant current can be set as per the battery capacity by using a potmeter and multimeter in series with the battery. Once the battery is fully charged,  it will attain certain voltage level (e.g. 13.5-14.2V in the case of a 12V battery),  give  indication and the charger will switch off automatically.You need not remove the battery from the circuit. If  the battery is discharged  b...

This is a Simple Voltage to Current Converter Circuit Diagram. This is an electronic circuit, The current out is Iqut—Vin/R. For negative currents, a PNP can be used and, for better accuracy,-a Darlington pair can be substituted for the transistor. With careful design, this circuit can be used to control currents of many amps Unity gain compensation is necessary. Simple Voltage to Current Converter Circuit Diagram  

This is a Simple 1 Amp Current Injector Circuit Diagram . A voltage booster provides the current control circuit with a higher voltage, to insure the electronic circuit operates properly, even as the battery voltage drops. A single LED provides both power monitoring and a low battery indicator. The current source is activated when a pushbutton switch is pressed. With a good digital voltmeter, you can use this device to measure resistances down to less than one micro ohm.   Simple 1 Amp Current Injector Circuit Diagram That is 0.000001 ohms. I often use it to measure contact resistance of a relay or the resistance of big chunk of heavy gauge wire or the resistance of a copper trace on a circuit board. You can also use it to measure the voltage drop of a power diode, when conducting one amp of current. 

This constant current circuit is designed to drive two 3-watt Luxeon LEDs. The LEDs require 1,000mA (1Amp) and have a characteristic voltage-drop across them of about 3.8v. Approximately 4v is dropped across the LM317T regulator and 1.25v across the current-limiting resistors, so the input voltage (supply) has to be 12.85v. A 12v battery generally delivers 12.6v. The LM 317T 3-terminal regulator will need to be heatsinked. This circuit is designed for the LM series of regulator as they have a voltage differential of 1.25v between "adj" and "out" terminals.