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Can a transistor be used to interrupt a signal? I know a common use is to switch power to another device. But my question is if I have a PWM signal applied to the emitter and the base pulled up, will the PWM signal make it through the transistor to the receiving device? Will pulling the base low disable the signal? Is there a better way to accomplish this interrupt without a relay?

To clarify, the signal is coming from a 3rd party device (RC receiver) and is used to control an ESC. I want to place a microcontroller in between to cut the signal off for certain conditions.

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closed as too broad by Scott Seidman, RoyC, Huisman, Sparky256, Chris Stratton Jul 24 at 19:35

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ Edit your question to explain what is generating the signal and what it is driving. Someone will answer. \$\endgroup\$ – Transistor Sep 28 '17 at 3:00
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    \$\begingroup\$ A schematic of what you are proposing couldn't hurt either. Are you using an IGBT? Otherwise you normally wouldn't have an emitter and a gate in the same device. \$\endgroup\$ – John D Sep 28 '17 at 3:03
  • \$\begingroup\$ Coincidentally, somebody asked a question about doing the same thing just 10 minutes before you asked yours. \$\endgroup\$ – The Photon Sep 28 '17 at 3:05
  • \$\begingroup\$ I updated the question with some more details. \$\endgroup\$ – Tanner Ewing Sep 28 '17 at 12:44
  • \$\begingroup\$ @JohnD my mistake, I meant base not gate. Updated to reflect \$\endgroup\$ – Tanner Ewing Sep 28 '17 at 12:46
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You may have better results using an actual logic gate for that, such as 74AC08. Feed the PWM into one input, the uC into the other. The output then follows the PWM while the uC signal is high, otherwise the '08 output is low. AC family has good drive capability, +/-24mA, at 0 and 5V.

If you want a really small SMD solution, there are also 5-pin, single gate solutions such as NC7SZ08. That one also has strong outputs, +/-32mA.

https://www.digikey.com/product-detail/en/on-semiconductor/NC7SZ08P5X/NC7SZ08P5XCT-ND/673391

Either way, add a 0.1uF cap from VCC to Gnd. For 35 cents, sometimes a simple gate makes more sense than messing with a transistor and current limit resistors and pulling the output high or low when it's inactive or adding a 2nd transistor to avoid inverting the signal.

Do you need more than a 0/5V signal? If so, what levels?

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... the signal is coming from a 3rd party device (RC receiver) and is used to control an ESC. I want to place a microcontroller in between to cut the signal off for certain conditions.

It seems on the face of it that you have described the solution. Read the PWM signal on a micro-controller input and pass it through to an output in the desired conditions - otherwise turn the output off.

The feasibility of this depends on the PWM frequency. You might need to use an interrupt input but the interrupt routine code could be very short and simple.

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