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I'm just an amatuer working with some electronics at home. I am trying to use an NPN transistor as a switch. 9v on the Emitter, 6v as the control on the Base to activate the switch, and I'm going to get 9+v on the Collector.

However, the voltages end up subtracting. When measured I only get 3v.

Am I setting this up wrong? I'm hoping to boost the voltage in this switch.

schematic

simulate this circuit – Schematic created using CircuitLab

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    \$\begingroup\$ Schematic? Hit control-M when editing your question to bring up this site's schematic editor. Note that for an NPN transistor, the emitter cannot be more than about 0.7 volts negative of the transistor's base. You should have a series resistor on the base connection to limit base current. \$\endgroup\$ – Peter Bennett Jul 14 '15 at 23:07
  • \$\begingroup\$ Schematic would make this an answerable question. I am a bit skeptical as to how you set it up. Could you add a simply picture? Or a common circuit your are trying to mimic? Thanks. \$\endgroup\$ – Josh Jobin Jul 15 '15 at 1:27
  • \$\begingroup\$ Also make sure if you can connect 6V signal to the base of the transistor.Absolute max rating of Vbe is 5V for ST9011. \$\endgroup\$ – Sanjeev Kumar Jul 15 '15 at 4:13
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I would think that your circuit would produce around 5V or more at the emitter of the NPN transistor, so I am thinking there is something not quite right somewhere. However your circuit will never work the way you want it to, so I am hesitant to spend too much time thinking about it.

Here is one circuit that will work the way you want. Just apply your 6V control signal to 9V_ENABLE. VCC_9V_SWITCHED will be 9V when 9V_ENABLE is high. You don't say how much current you are expecting. So I am not sure if the BSS84 is really a good choice. If you add a current requirement on the 9V supply, someone might be able to select a better choice for M1.

Good luck and keep at it!

schematic

simulate this circuit – Schematic created using CircuitLab

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