*On 7 January 2014 14:58, Sergey Dryga > wrote: * > > > > > > * If PIC is driving the gate, then make sure the MOSFET is "logic" MOSFET= , > sothat 5V completely turns it "on". Your device (STP36NF06L) does not > switchcompletely "on" at Vgs=3D5V. This will lead to reduced current (Id= ) > and higher thermal dissipation. Look at Output characteristics (Figure 3 > indatasheet) and Transfer characteristics (Fig 4).* > Yes. Beware that vthere are L and FP versions Datasheets here: FP is v marginal http://www.st.com/web/en/resource/technical/document/datasheet/CD00003408.p= df At 5V it's staggering into life - fig 5, 2V Vds at 8A typical - not nice - there are many more that are properly on at 5V and a lot that can be driven with 3V. L version is better - but better again can be had for similar $ http://www.st.com/web/en/resource/technical/document/datasheet/CD00003405.p= df What Imax ever? What Vmax ever? SMD or through hole wanted.? What max PWM freq ever? Vgs may be > Vds with no problems. 12V zener gate-source close to FET protects against most problems from inductive load coupling into gate from Cdg Miller capacitance. Direct PIC to gate drive allows only low freq PWM. DC switching OK. Russell --=20 http://www.piclist.com/techref/piclist PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .