Capacitive coupling on breadboard

In summary, the conversation discusses the concept of parasitic capacitance and its effects on signal noise in circuits. The speaker struggles to understand the role of time varying electric fields compared to magnetic fields and seeks clarification on how capacitance between nodes can lead to noisy signals. A possible solution is suggested, involving the use of an Earth plane to reduce the impact of 25 pF of capacitance between breadboard nodes.
  • #1
FOIWATER
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I have read that between breadboard nodes there can be as much as 25 pF of capacitance.

I have a much better time understanding how parasitic induced voltages work, with respect to magnetic fields.

I have a much harder time understanding how signals can become noisy due to parasitic capacitance.

I don't understand time varying electric fields as well as magnetic fields.

Can some one help me understand how capacitance between nodes, can manifest itself as a noisy signal in said circuits?
 
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  • #2
Capacitative coupling is more straightforward than magnetic coupling, imo. Just consider it as joining a capacitor of 25pF or so between the two nodes and work out the effect of this in terms of a simple (based on impedance, not just resisitance) Potential divider to find the induced voltage.

There will be layouts possible that should give a bit lower than the 25pf you quote, I think, if it's a problem but it depends upon the actual circumstance. Using an Earth plane can help a lot.
 

1. What is capacitive coupling on breadboard?

Capacitive coupling on breadboard is a phenomenon where two conductive elements on a breadboard are connected by a small capacitance, often caused by the proximity of the elements or their physical contact. This can create unwanted electrical connections and interfere with the desired circuit behavior.

2. How does capacitive coupling affect breadboard circuits?

Capacitive coupling can cause unintended connections and interference in breadboard circuits, leading to unpredictable behavior and possible malfunctions. It can also introduce noise and affect the accuracy of circuit measurements.

3. How can I reduce capacitive coupling on my breadboard?

To reduce capacitive coupling on breadboard, you can try to increase the distance between the conductive elements, use shorter wires, or add decoupling capacitors to the circuit. You can also use specialized breadboards with built-in shielding to minimize capacitive coupling.

4. Can capacitive coupling be beneficial in breadboard circuits?

In some cases, capacitive coupling can be beneficial in breadboard circuits. For example, it can be used to create intentional connections between elements or to filter out unwanted frequencies. However, it is important to carefully control and consider its effects in the circuit design.

5. How can I test for capacitive coupling on my breadboard circuit?

You can test for capacitive coupling on your breadboard circuit by using a multimeter to measure the resistance between different conductive elements on the breadboard. If there is a low resistance reading, it may indicate the presence of capacitive coupling. You can also use an oscilloscope to observe any unwanted signals or noise in the circuit.

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