HeY Carl !

[Vasil]

Are you sure that Q11 / page2, opt.2/ must be NPN ???

[Carl-NC]

If Q11 is NPN, then Q7/Q11 form an SCR-type circuit. If Q11 is PNP, then Q7/Q11 form two stages of common-emitter amps... problem is, Q7 will need a resistive collector load, and Q11 will likely be biased 'on' all the time, unless some other measures are taken.

Short answer is, yes, Q11 should be NPN.

- Carl

[Vasil]

HeY Carl!

Q11 is very hot in this cirquit. See emiter Q11 whith osciloscop.

[Carl-NC]

Both Q7 and Q11 turn on with a short duty cycle pulse, and should not get hot. Haven't heard anyone else mention this either.

- Carl

[vASIL]

hey CARL!

If signaljf Q11 is inverting ,Q11 will be hot. Sorry! My Q11 is BC337 /npn-0,8w , h21e-430/ and hoting.