Will an inductive load damage my function generator? Will the circuit I'm designing damage my function generator shown below.
I'm using this function generator which has an output impedance of 50 ohms: https://www.gsi-protek.com/9205a9205c
Electronic – Will a purely inductive load damage the function generator
function generatorinductiveinductor
Related Solutions
500kHz is a ways past the maximum specified frequency for square waves for this generator: 100kHz. It appears to have a single-pole RC of about 3.5µs, which would work great for a 0.35/(3.5µs)=100kHz square wave. The output may have a LPF for slew limiting. Also, it is a 50Ω source, so it should be terminated properly to avoid ringing. Try using the TTL and CMOS waveforms, too. B&K have put together this document: Function & Arbitrary Waveform Generator Guidebook .
The external CMOS inverter is not a 50Ω source -- it's source impedance is only a few ohms at most (for low currents) due to VCC and ground impedances and FET RON equivalent resistances. Notice that the output duty cycle isn't 50%, and the edges are ringing.
The 50 Ohm internal resistance changes the behavior from that of an ideal signal source is one simple manner: It behaves just like adding a 50 Ohm resistance in series with the voltage source, completing the circuit through your load:
simulate this circuit – Schematic created using CircuitLab
As the function generator is specified with an internal resistance of 50 Ohms, its signal specifications would be for a 50 Ohm load.
For example, for a 5 Volt signal output setting, and using a matched 50 Ohm load for X above, the current through the loop will be: I = V / R = 5 / 100 = 50 mA. This is the nominal, specified case. As load 'X' is changed, the current drawn will change, and thus the voltage across the load changes correspondingly.
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Best Answer
It should be just fine.
Your function generator will look like a low source impedance 400mV p-p source (like an op-amp output but beefier) with a 50 ohm resistor in series, so the complete circuit is not purely inductive (not that it's a problem).
The inductor has an impedance of \$2 \pi f L\$ for a sine wave or about 7.5 ohms.
Any decent commercial function generator should not be damaged by even shorting the output or connecting it to arbitrary impedances, and these levels are pretty benign. 4mA peak into even a short circuit is nothing to be concerned about. Don't try a 100uF capacitor charged to 300VDC though. Your function generator can supply 100mA peak into a 50 ohm load.