May 15, 2009 #1 H hakeen Full Member level 5 Joined Jun 16, 2005 Messages 240 Helped 44 Reputation 88 Reaction score 19 Trophy points 1,298 Activity points 2,783 off state capacitance Hello I have a SSR (aka PhotoMOSFET). The inner structure is shown below. it is 60V, up to 1A at MOSFET side. How can I measure the off-state capacitance of the MOSETs of the component? Thanks for any help. Regards Hakeen
off state capacitance Hello I have a SSR (aka PhotoMOSFET). The inner structure is shown below. it is 60V, up to 1A at MOSFET side. How can I measure the off-state capacitance of the MOSETs of the component? Thanks for any help. Regards Hakeen
May 15, 2009 #2 E eem2am Banned Joined Jun 22, 2008 Messages 1,179 Helped 37 Reputation 74 Reaction score 24 Trophy points 1,318 Activity points 0 1. turn it off 2. measure the capacitance. ..as follows..... i = cdv/dt shove a resistor in series with the terminals 3 and 4 shove a square wave across this RC combbo. Take a look at the voltage across the terminals 3 to 4. Use Laplace to get the capacitance. or just use 5RC = time to aiming voltage im sure you can work the rest out from here. you must see i = cdv/dt you know i(t) = v(t)/R v(t) = v across res In fact. i(t) = V/R * (1-e(-Rt/L))
1. turn it off 2. measure the capacitance. ..as follows..... i = cdv/dt shove a resistor in series with the terminals 3 and 4 shove a square wave across this RC combbo. Take a look at the voltage across the terminals 3 to 4. Use Laplace to get the capacitance. or just use 5RC = time to aiming voltage im sure you can work the rest out from here. you must see i = cdv/dt you know i(t) = v(t)/R v(t) = v across res In fact. i(t) = V/R * (1-e(-Rt/L))