This is the 3rd (and final) part of a series of posts on the Hantek CC-65 current clamp probe. In part 1 we went over the probe structure and circuit operation, and discussed possible issues and improvements. In part 2 we’ve started measurements and modifications of the probe, focusing on the power-supply (PS) and the sensor bias circuit. That allowed us to achieve lower noise on the supplies and sensor bias, as well as extend the circuit operation down to lower battery voltage.
In this post I’d like to go into modifications of the actual signal chain. This consists of the amplifier structure at the heart of the probe, but will also touch on the offset cancellation circuit. The main goal from my point of view is to both extend its bandwidth (BW) by at least an order of magnitude, and reduce the equivalent input noise density so that limited BW measurements can be made on lower amplitude signals.
Continue reading “Hantek CC-65 Current Clamp Probe – Part 3 – Signal Chain, Improving BW and Noise”
In the previous post we’ve gone over the CC-65 probe structure and schematic, and noted a few things that can be done to improve its performance. Other than modifying the probe with higher spec parts, there were a few design decisions and potential issues that were discussed. In this post I plan translate the previous discussion into actual measurements and modifications to the probe. I will cover only part of the circuit in this post, and will cover the rest in a follow up post. This time we’ll have a look at the power-supply and biasing circuit, while the actual amplifier/signal path will be covered in the next post.
I should start by saying that the parts shortage observed nowadays is affecting this project too, it is one of the reasons it took such a long time to get something done. In fact, even now, I’ve had to opt for some replacement parts which weren’t my preferred option, or else it would call for months of wait for parts to be back in stock. With that said, lets move on to some actual measurements.
Continue reading “Hantek CC-65 Current Clamp Probe – Part 2 – Basic Measurements, Power-Supply Modifications”
This post will discuss the Hantek CC-65 current clamp probe, a cheap and useful tool. I’ve ordered this probe because of its low cost, and reasonable performance. I was happy to see there’s even a schematic for it available online as drawn in a post on the EEVblog forum. Looking at the schematic made it clear there’s a lot that can be done to improve it fairly easily. Due to the length of the post, and the fact I’m still waiting for the parts to arrive, I’m going to split this post into a few parts. In this part we’ll go over the operation of the probe and its schematic, and then discuss possible modification that can be made to it. There are quite a few tradeoffs to be made in the selection of parts and which mods to do, based on the requirements out of the probe. I will detail some of these considerations, and in the next parts will present results based on the mods I’ve decided to implement according to my preferences.
This part turned out to be quite long with a lot of text and little pictures/results. I think this is of value and will serve as good background and reference in the next parts on this topic where measurement data will be presented. There, it will be possible to simply point to the relevant part of the current post, to explain the reasoning behind chosen components for mods, and measurement results explanations.
Continue reading “Hantek CC-65 Current Clamp Probe – Part 1 – Probe Analysis and Discussion”