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1
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1answer
54 views

Suppressing BLDC Motor noise? Is it radiated or a grounding issue? [closed]

I have a BLDC motor that rotates an imaging assembly(ultrasound) and alot of PWM noise can be seen in the resultant image produced. If I play around with the RX line that carries the imaging signal ...
8
votes
2answers
192 views

Transient voltage suppression diode not doing its job

I have a circuit which works on 21V DC and draws 3A maximum current. I need to get it tested to IEC 61000-4-4 and 61000-4-5 standards which are surge immunity tests. I use a UL certified switch mode ...
3
votes
3answers
154 views

TVS specification understanding

I have some questions regarding Transient Voltage Suppressors (TVS). The specific datasheet I'm referring to is this, from 1SMB22AT3G. Here is some of its specs: \$V = 22V\$ \$V_c = 35.5V\$ ...
3
votes
2answers
157 views

How to suppress current spikes in transistor feedback loop

I am trying to pulse a load with a small constant current pulse (2mA @ 500us). The load does unfortunately have an unknown capacitance in the range 10nF - 1uF, parallel with an unknown resistance ...
1
vote
2answers
71 views

Surge suppression for electric motor

I have a 4.2W 12V electric water pump connected in series with a water float switch as a sump pump, powered by a 1A 12V DC power brick. The switch has a maximum switching voltage rating of 100V. ...
2
votes
1answer
207 views

Transient Voltage Suppressor (TVS) Diode Array

I am having a hard time understanding this logic. Please bare with me if my question is very basic. I would appreciate if someone can explain what is happening? If I look into any typical TVS IC data ...
4
votes
1answer
118 views

Current-sense for NES/SNES gamepad detection - getting a voltage spike

I'm in the process of designing a wireless controller receiver for the NES/SNES game consoles. My wireless receiver consists of a bluetooth module and an AVR microcontroller, with the microcontroller ...
4
votes
2answers
200 views

Regarding ESD diode's architecture

I need one clarification regarding ESD,EFT and SUrge protectors. Different manufacturers have architectures of diodes+Zenar diode combinations for different protection levels for different interfaces. ...
1
vote
2answers
198 views

Varistor S10K30 for 24-40VDC input?

I was put in charge of redesigning a motor control circuit which accepts 24-40V DC on its input. As a side note: As far as i know, the existing circuit has been working fine for several years. The ...
5
votes
1answer
297 views

Help tame turn-on transient

I'm working on a dual headphone amplifier. I've discovered that it has a pretty bad turn-on transient that results in a loud pop if headphones are plugged into the amplifier when it is turned on. ...
5
votes
3answers
530 views

How to properly snub transient spikes from a transformer and prevent switch mode power supply burn out

I've received a failed switch-mode DC-DC step down converter (part# LTC3631 from Linear). This circuit was driven by a 24VAC transformer which is rectified on the circuit: simulate this ...
9
votes
1answer
2k views

How to decide between a TVS or Zener diode for overvoltage protection?

I'll leave my specific circuit out of this for a more broad question: What criteria does one use when deciding whether to use a Zener diode or a transient voltage suppressor, for overvoltage ...
8
votes
2answers
2k views

What are bidirectional Zener diodes used for in DC transient protection?

I often see two zeners (in opposition to each other) being placed across the power supply rails. I don't understand why that is necessary. For example, if I have a 16V Zener diode and a 12V power ...
9
votes
2answers
2k views

Flyback diodes issues and pull-in & hold current issues in this Relay circuit

Although this may be a basic question but I'm still struggling with it. In this schematic, two zener diodes D1 and D2 are connected back-to back across relay coil L1. The BVds = -30V for Q1. Can I use ...
4
votes
1answer
166 views

How does a high voltage condition break down a semiconductor?

I have TVS diode in parallel with circuitry for ESD/lightening/transient voltage protection. Say I receive an over-voltage condition which is beyond the specifications of the part, what happens ...
4
votes
2answers
975 views

Long supply line and capacitor to prevent voltage drop

I have a 30 feet line with DC supply 12 V. A motor on the end draws about 0.5 Amps initially (100 ms). It's logic shuts down because of the line's voltage drop caused by inrush current. A capacitor of ...
15
votes
3answers
4k views

How to limit inrush current?

I'm designing a device powered from USB. The device uses FTDI FT2232 chip for USB connection. Upon a command from a computer FT2232 chip should enable power via a MOSFET switch to rest of the circuit. ...
3
votes
2answers
302 views

Are transient suppression diodes necessary for a battery powered system?

I've seen on designs where there is a TVS transient suppression diode on the voltage supply. For example, when the voltage supply is say a wall plug. However, are such diodes really necessary in a ...