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58 Threads found on Mosfet Series Resistor
Just add a mosfet on the 555's output, driving a speaker.
hi, On a simple circuit like that I would use a low value resistor in series with the Source connection of the mosfet. Sense the voltage drop across the resistor using say a LM393 comparator. Add a resistor/capacitor filter on the input or the output of the comparator that connects to the sensing control (...)
Hi, I don't like the direct connection of a capacitor on a mosfet switching signal. I think a 10 Ohms series resistor is useful. Klaus
Try to see whether you can put 2 or 3 led's in series. Each string needs a resistor (several hundred ohms). Thus if your strings are 2 led's each then you'll need 75 resistors (maybe 400 or 500 or 600 ohms). If 3 led's each then you'll need 50 resistors (maybe 200 or 300 or 400 ohms). Brightness depends on how well the (...)
Is it OK to drive the gate of a low-power mosfet from the drain of another low-power mosfet of opposite polarity, directly without an external series resistor? I'm thinking in terms of the current spike when the gate charge is being pumped in at the moment of switching. I'm concerned about both the driver and the driven (...)
I am using UC 1708 driver (with capability 3A) at 15V to switch 2N6766 power mosfet (frequency 100kHz). Gate series resistor is 10E. There is a zener diode 1N759 and 4.7 k between gate and source of the mosfet . The gate transient current peak is 350 mA. What is limiting the gate current to 350mA, when 1708 can supply 3A?
Check compensation components add current sense filter Check sense resistor is downsized to allow for slope ramp if in current mode. Check sense resistors of right value. Check the design is correct in terms of inductor values etc. Is sense resistor near to controller Is there enough series resistance with the (...)
I am working on H-bridge circuit with PWM. It is basically class-D amplifier with four N-channel mosfet. However, i am stuck at one-point. How to calculate the drain current for high side mosfet? The configuration is shown in figure. I am applying 30V Gate voltage(Respect to Ground). Drain is connected to the positive power supply rail of 20V.
It is impossible that the internal resistor is 10K, it must be 10 ohm. 10K will slow down the mosfet so much that it will be useless. I recommend you use external zener, 1 is enough if your drive is positive only. A series resistor too of 100 to 470 ohm, depending on the frequency.
You are welcome Mobin! About you questions: 1,2) Your transistor you have to Calculated impedance of 1304 ohms , but the Rg needs to charge and discharge the Cgd Cge and fast , to limit generator 's current and to Prevent auto- oscillations too . I have some formulas, I think you can check them , however I , in transistor 's datasheet some va
I guess the internals are like a mosfet with a protection diode? Does that sound correct? Yes, 2 protection diodes, one to GND & one to VDD, with a common protection series resistor. In the general description it states "In the off condition, signal levels up to the supplies are blocked."
) I'm using a PIC18F4550 and the relay I want to switch is a V23026A (TE-Connectivity). 1. I guess I can use the uC directly to switch the relay since it is possible to source/sink a current up to 20mA and the relay nee
hi, there is a question. to design proper drive I implement a very simple circuit. I turn on a DC lamp with a mosfet. why when I reduce gate resistor ( from 120ohm to 18ohm), the mosfet does not get fully saturated and the lamp turn on with reduced light and mosfet gets hot. obviously it work in active region. why? , while (...)
Hi all , i picked this one circuit to drive three smd 5050 led modules , current is set at 180mA with formula Rs=0.7/I Rs =3.9E i made Rs with 15E and 5.6E parallel PROBLEM : the mosfet IRF840 heat al little nicely after 4 hours , i want to keep it cool w/o any heat sink But IRF 840 can handle more is not it
Instead of an electromagnetic relay you can use a mosfet switch, also optocouplers can be used for powering a LED from two separate sources., As a LED requires a series resistor to limit a specified LED current , then you need two such resistors, one for 3V, another for 24 V. You did not indicate what other load is to be (...)
Hello, I've a doubt about positioning TVS to protect a mosfet from ESD's and other over-voltages. The application is no critical regard switching time so I place a 120Ω resistor in series with gate to reduce gate current during switching. I think it's a good idea to place a TVS between gate-resistor and GND (...)
Dear All I am using mosfet in Dual feed convertor mode for driving Inductor coil for Mechanical Vibration as given in AN of IR2110 . I Modified the connection and Ckt is attached here.The Circuit is driven by the PWM pulses from Arduino UNO with default PWM frequency 455Hz. As I start it Both mosfets and IR2110 get Blast.I remove the Q1 Q2 D2 and
Dear all, i have been facing the problem of mosfet drivers. pls check the attachment & feedback me so i can make the respective changes. pls pls pls - - - Updated - - - mosfet is FDD 8870
I'm designing an IR transmitter for a college project based on binary fsk. I'm using an astable 555 timer running at 126KHz to directly drive a N-Channel mosfet. Vs in this project is 9v. I have 3 IR diodes in series with a resister connected to a Vs. The mosfet is on the low side of the circuit so that when the 555 timer output goes high it (...)
A buffer can be necessary i you need to drive a capacitive load with fast edges, e.g. a PWM switching mosfet, or a clock line.