Problem with voltmeter / probe voltage display across LED
Quote from JimH on September 25, 2026, 2:25 amSimulIDE 1.1.0 R1912, Ubuntu 24.04
I created a simple circuit to show the operation of two-way light switching. Circuit file is attached.
Start the simulation with Switch-1 in the down position and Switch-2 in the up position. Turn on the 5V Fixed Voltage. Voltmeter-1 shows 5.000V, Voltmeter-2 shows 0.000V and both probes show 0V. This is as expected.
Change the position of either switch, Voltmeter-1=5V, Probe-1=5V, Probe-2=2.4V, Voltmeter-2=2.405V, Led-1 is on. Again as expected.
Change the same switch back to its original position, the problem becomes clear. Voltmeter-1 still shows 5V but Probe-1 drops to 2.4V, Probe-2 and Voltmeter-2 show 2.4V. The Led is off. The voltage should have returned to zero except on Voltmeter-1.
It the Fixed Voltage is turned off while the probes and voltmeter-2 incorrectly show 2.4V, there is no change except Voltmeter-1 correctly shows 0.000V
The problem can be corrected by the addition of 100GOhm resistance in parallel with Led-1 possibly suggesting that the LEDs require the addition of some leakage current?
SimulIDE 1.1.0 R1912, Ubuntu 24.04
I created a simple circuit to show the operation of two-way light switching. Circuit file is attached.
Start the simulation with Switch-1 in the down position and Switch-2 in the up position. Turn on the 5V Fixed Voltage. Voltmeter-1 shows 5.000V, Voltmeter-2 shows 0.000V and both probes show 0V. This is as expected.
Change the position of either switch, Voltmeter-1=5V, Probe-1=5V, Probe-2=2.4V, Voltmeter-2=2.405V, Led-1 is on. Again as expected.
Change the same switch back to its original position, the problem becomes clear. Voltmeter-1 still shows 5V but Probe-1 drops to 2.4V, Probe-2 and Voltmeter-2 show 2.4V. The Led is off. The voltage should have returned to zero except on Voltmeter-1.
It the Fixed Voltage is turned off while the probes and voltmeter-2 incorrectly show 2.4V, there is no change except Voltmeter-1 correctly shows 0.000V
The problem can be corrected by the addition of 100GOhm resistance in parallel with Led-1 possibly suggesting that the LEDs require the addition of some leakage current?
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