Transistor voltage measurement

[Tommy8389]

By using voltmeter. How to measure the voltage of collector and emitter. Vbc is the collector voltage and Vbe is the emitter voltage? And how should my voltmeter place? Sorry for the silly question

 

[Herschel Peeler]

By using voltmeter. How to measure the voltage of collector and emitter. Vbc is the collector voltage and Vbe is the emitter voltage? And how should my voltmeter place? Sorry for the silly question

If you want to measure the voltage between the emitter and the collector that is where the meter leads go. Is your question more complicated? Start with a data sheet for the transistor in question.

 

[Audioguru]

Vbc is the voltage from the base to the collector.
Vbe is the voltage from the base to the emitter.
Vce is the voltage from the collector to the emitter.

 

[duke37]

The circuit will have a ground connected to many stages.
Measure the voltage between ground and emitter.
Measure the voltage between ground and base.
Measure the voltage between ground and collector.

Some subtraction will give the voltages required.
With an npn transistor, the voltages relative to ground will rise from emitter to base to collector and there is likely to be about 0.6V emitter/base.

 

[Tommy8389]

The circuit will have a ground connected to many stages.
Measure the voltage between ground and emitter.
Measure the voltage between ground and base.
Measure the voltage between ground and collector.

Some subtraction will give the voltages required.
With an npn transistor, the voltages relative to ground will rise from emitter to base to collector and there is likely to be about 0.6V emitter/base.

I placed my voltmeter's positive at the base and the negative at collector. When the transistor is "OFF". I get negative voltage (-0.78v). When the transistor is "ON". The voltage is 0.72v. can you explain for me why? Or i placing it at wrong polarity? Thanks.

 

[Bluejets]

NPN or PNP?

 

[Tommy8389]

NPN or PNP?

Npn

 

[Tommy8389]

Ok thanks guys. I found out why there is a negative voltage occured when transistor is off. After i read through the cut-off mode.

 

[BobK]

Why are you measuring from the collector to the base? The more useful measurements are from the emitter to the base and from the emitter to the collector.

Bob

 

[Audioguru]

We do not have a clue about your transistor circuit because you did not attach its schematic to this thread. The schematic will show the part number of the transistor, the supply voltage and the resistor values. Something (maybe a switch?) on the schematic will turn the transistor on and turn it off. Then we will know all the details.