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I recently sought (and received much great help) help with a brake light project from this site. That project went well and I installed it a week ago. Everything seems to be working as intended thus far. However, I am interested in playing around with some potential variations to the design of the circuit.

I ordered most of my parts for that build online from Digi-Key and Mouser. However, I did not have enough extra VN10LP N Channel MOSFETS to complete an identical circuit.

I went to my local RadioShack today and got 4 N-Channel power mosfets to hopefully use in place of the VN10LP mosfets.

My application is straightforward: the n-channel MOSFETs are being used simply to provide HIGH or LOW signal to pins on an Octal Counter IC.

Looking at the ratings of the power mosfet, all of the ratings are more than adequate for the circuit's current and voltages.

Therefore, are there any potential pros/cons to using a POWER MOSFET versus a regular MOSFET in a simple, low speed switch application??

Data sheets for each:

VN10LP N Chan MOSFET VN10LP

IRF510 N Chan POWER MOSFETIRF510

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You should not only consider the requirements for the output section (source and drain). The gate section behaves as a non-linear capacitive load. A power mosfet requires the application of a high peak gate current and a reasonable gate voltage value (remember that is not suffice to reach Vth). Frequently someone says that the advantage of a mosfet over a bipolar transistor is that the former is driven by voltage and not current. But this is a very incomplete statement, in the case of power mosfets. Depending on the application it's necessary that the gate driver circuit provides several amperes in a short time. In addition, other capacitances are present in a power mosfet that you must deal with. In other hand, there are also standard mosfets with low values for RDSon. Therefore not justify the use of a power MOSFET in standard applications just for this reason, for example.

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In addition to the Cgs parasitic, you have to weigh the price and size of using a Power FET for a low current signal switching application. Obviously, you use what is available for prototyping.

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