timelessbeing
Member
Hi everyone. I bought an inexpensive 20A hall effect sensor board on eBay, and then decided to build a simple meter out of it. I breadboarded the circuit, and it appears to work. What do you experienced guys think about it? Is the design "sound"?
The voltage regulator runs a bit hot (12V input), but I measured 60mA on the output which is within spec. It has automatic thermal shutdown anyway.
I chose such low resistor values to overcome the current flowing through the voltmeter (which only has 20kohm). I considered using an opamp to buffer that end. It would be more elegant, but it added more components and complexity, and 50mA seemed okay to me so I decided bugger it. The 1/4W resistors are only dissipating 1/10W. I could still raise the value of those resistors a bit without sacrificing too much accuracy. (I only wanted 5%) Thoughts?
If I wanted to read the AC signal with a scope, I could simply probe the V(o) since it has much higher impedance right?
Thanks for reading.
The voltage regulator runs a bit hot (12V input), but I measured 60mA on the output which is within spec. It has automatic thermal shutdown anyway.
I chose such low resistor values to overcome the current flowing through the voltmeter (which only has 20kohm). I considered using an opamp to buffer that end. It would be more elegant, but it added more components and complexity, and 50mA seemed okay to me so I decided bugger it. The 1/4W resistors are only dissipating 1/10W. I could still raise the value of those resistors a bit without sacrificing too much accuracy. (I only wanted 5%) Thoughts?
If I wanted to read the AC signal with a scope, I could simply probe the V(o) since it has much higher impedance right?
Thanks for reading.