This answer shows a circuit including a LM311N voltage comparator. Its stated purpose is to be a oscillator, allowing identification of an unknown inductor L1. It has similarities to the Free-Running Multivibrator shown in the datasheet. I expected that the resonance frequency of the tank circuit L1 and C7 would introduce a square wave due to the comparator, thus allowing to calculate L1 due to a known C7.
Trying to understand it, I simulated it in SPICE with a LM311 model from a forum. Furthermore I replaced the LM311 with the LT1011, which claims pin compatibility to the LM111 (~LM311 with extendet ratings). The tank circuit oscillates with a starting peak of 12..20mV until it dies out within less than 200 µs in both simulations. I also tried to change resistor values and introduced series resistances for L and C to start the oscillation, but to no avail.
Building the physiscal circuit on a stripboard provided no useable results when I measured the available potentials with a scope.
How can the circuit be used? What behaviour should it show?
I had problems understanding the circuit, as it connects the collector output straight to Vcc, while the emitter is connected to ground over its internal 4 \$\Omega\$ Resistor.