Fet Led schematic
The circuit described utilizes a Field Effect Transistor (FET), specifically the BF256C, to control the current flowing through an LED. The FET operates by using voltage applied to its gate terminal to modulate the current between the source and drain terminals. This allows for efficient control of the LED brightness based on the input voltage, which can range from 4V to 30V.
In this configuration, the LED is connected in series with a current-limiting resistor to ensure that the current remains constant at approximately 15mA, which is optimal for typical LEDs to prevent damage while providing adequate brightness. The resistor value can be calculated using Ohm's law, factoring in the forward voltage drop of the LED, which is typically around 2V for standard red LEDs. For example, if the supply voltage is 9V, the resistor value can be calculated as follows:
R = (Vsupply - VLED) / ILED = (9V - 2V) / 0.015A = 466.67 ohms.
A standard resistor value of 470 ohms can be used in this case.
The circuit also allows for AC power supply operation, which may cause the LED to dim slightly due to the nature of the alternating current. The diode (D1 = 1N4148) serves as a rectifier, allowing only the positive half-cycles of the AC signal to pass through, thus converting the AC supply into a pulsating DC supply. This characteristic may result in a noticeable reduction in brightness compared to a purely DC operation.
Overall, this circuit provides a simple and effective means of controlling LED brightness using a FET while allowing for flexibility in power supply options. Proper consideration of component ratings and characteristics is essential for optimal performance and reliability.This circuit uses the effect of a FET as the power to act through the gate with the source to connect. The voltage may vary between 4V and 30V, the current through the LED should constantly be around 15mA.
The circuit can also be powered by AC, the LED will dim slightly. T1 = BF256c D1 = 1N4148 Simple LED = LED 🔗 External reference
Related Circuits
This month's project is based on the 4017 chip that was used in a previous project. It is advisable to review the fundamentals of the 4017 chip as presented in last month's project. The circuit has been modified slightly;...
This circuit generates sine and square wave signals with frequencies ranging from below 20 Hz to above 20 kHz. The advantage of this circuit diagram is that the output frequency can be adjusted by varying the variable resistor R6. The...
In the project, the LCD data ports are connected to port 1 of the controller, while the control pins, namely RS, E, and R/W, are connected to pins 3, 5, 6, and 2, 1 of the controller. The LCD...
The electronic lock circuit is based on the frequency characteristics of the LM567 audio decoder. This circuit utilizes the audio decoding feature of the LM567, which outputs a low signal when the input signal frequency matches the oscillation frequency...
Electronic Schematic Circuit Diagrams Manual PDF Download. The document provides a comprehensive manual that focuses on electronic schematic circuit diagrams. These diagrams are essential tools for understanding and designing electronic circuits, offering visual representations of circuit components and their interconnections....
This is a high-fidelity, high-quality audio amplifier circuit diagram. A pre-amplifier is not required. Component list: R1, R4 = 47K 1/4W resistors; R2 = 4.7K 1/4W resistor; R3 = 1.5K 1/4W resistor; R5 = 390Ω 1/4W resistor; R6 =...