# Tag Info

Accepted

### How can I build an impedance measurement circuit?

The upper shown approach is good to with, you can design this simple circuit in terms to calculate the impedance parameters easily. Btw, Arduino has only 10 bit ADC keep that in mind, I will suggest ...
Accepted

### Calculating dimentions of impedance-matched pads on PCB in an RF circuit

Trace impedance calculations are a bit misplaced here. More likely, these pads are under 1/4 wave width/length, so can't really be said to be transmission line structures. What's more, the fact that ...
• 41.3k

### How can I build an impedance measurement circuit?

Basically you have to supply a (sinusoidal) signal and measure the ratio of voltage applied to current flowing. This can be done with your Arduino, some opamps and some calculations. For an example ...
• 19.5k
1 vote

### Why does the resonance peak dampen when an air cored coil is kept on a conducting material?

When you use a "conducting" material with a coil in the neighborhood, you create a "coupled" LC circuit with a "low" factor of "coupling" kc. Here is the ...
• 14.7k
Accepted

### Why does the resonance peak dampen when an air cored coil is kept on a conducting material?

If there are eddy currents in the material then some energy is going to be lost as heat. That loss of energy has the same affect as any other loss in the coil, it reduces the Q, which leads to a lower,...
• 25.6k

### Why does the resonance peak dampen when an air cored coil is kept on a conducting material?

Eddy currents in the plate not only reflect back to the exciting coil to change its inductance, but the eddy currents in the plate heat it up, due to the plate's internal resistance. The power ...
• 26.8k
Accepted

### Inverting Amplifier for Impedance and Scaling before Electrosmith Daisy Seed

Not sure why you decided to go with an inverting amplifier, but you could try a voltage divider followed by a non-inverting unity gain buffer. Something like this will give you around 860k input ...
• 25.6k
1 vote

### Inverting Amplifier for Impedance and Scaling before Electrosmith Daisy Seed

No, it won't work. If you bias the +ve input to VCC of the op-amp, then output bias is also VCC, and it would mean that when input has a negative transition below VCC, the output would have a positive ...
• 161k
1 vote
Accepted

### Is it possible to bound the characteristic impedance of a connector pin if it's not impedance-controlled?

Free space is a practical limit. An example of a transmission line with a characteristic impedance higher than that of free space is an air-filled coaxial cable with a very large inner conductor ...
• 146k