How to measure the constant resistance of small bulb if there is only voltmeter but no ammeter

How to measure the constant resistance of small bulb if there is only voltmeter but no ammeter

Voltammetry "resistance measurement" is to measure the current and voltage of unknown resistance with ammeter and voltmeter, and then calculate the resistance according to Ohm's law. If only one ammeter (such as voltmeter) is given to measure the resistance, the current can be measured through a constant resistance with known resistance value. The specific methods are as follows: (1) let the constant resistance

In the absence of an ammeter, measure the resistance of the value resistance with a voltmeter and a sliding transformer

In this paper, a series connection is made between the rheostat RP and the setting resistor R, and a voltmeter is used to connect the rheostat in parallel. 1. When the rheostat is set to the minimum, the resistance of the rheostat is 0, and the measured voltage of the setting resistor is the power supply voltage U; 2. When the rheostat is set to the maximum, the maximum value of the rheostat is known from its model, and the measured voltage of the setting resistor is U1, so the current in the series circuit is I = (u-u1) / RP, So r = U1 / I = U1 * RP / (u-u1), over

The problem of converting sensitive galvanometer into voltmeter or ammeter
When a sensitive galvanometer was converted into a voltmeter,
Sensitive galvanometer pointer deflection, indicating the measured voltage, (if the dial is 0 to 3V)
However, does his indication also indicate the current passing through the sensitive galvanometer (at this time, read according to the range of the sensitive galvanometer, if it is 0 to 3 MA)

Yes, the galvanometer was changed into a voltmeter, only a large resistor was connected in series, and the measuring range was changed accordingly

Voltmeter and ammeter are sensitive galvanometers with partial resistance. Why can't they be used in series? What's the difference between the specific internal structure?

The voltmeter is a sensitive galvanometer with voltage divider and series voltage divider
All ammeters are sensitive galvanometers with shunt resistance and shunt in parallel
It's not absolutely impossible to use the voltmeter in series. It's just that the resistance of the voltmeter is large. When the voltmeter is connected in series with the ammeter, the branch current is very small. The ammeter almost has no reading, which makes people feel that the circuit is open. But in fact, the voltmeter still shows the number