Flyback Transistor

Senscomp said:

The #614096 Ranging Transformer, and the #619391 (6500) Ranging Transformer are both used the same way.
The input is listed as a DC voltage due to the way it is used in the circuit. If you look at the 6500 Ranging Module schematic, one side of the transformer (T1) is tied to +5V DC, while the other side is pulsed using a transistor (Q1). The input to the transistor can be a burst of 1 to 20 pulses at a 50 KHz rate. There should also be a time of rest between the bursts of pulses. When the pulses are stepped up by the transformer, the output is a 400Vpp burst of 50 KHz that will drive the electrostatic transducer. The zener diodes (CR1-4) placed on the output of the transformer will protect the transducer from possible damage due to excessive voltage.
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ronsimpson said:

I may be looking at a different schematic…but
I do not know if the flayback is operating in resonance or non-resonance mode.

non-resonance (no capacitor): Then the transistor is on, current builds up in the primary of the transformer with time and voltage divided by inductance. That is to say the longer the time is the more current (power) is stored on the transformer. Then the transistor opens up the voltage on the collector will go up until it finds a limit somewhere. (load, or the 400 volt zener, or the breakdown voltage of the transistor) Running slow will slam more power into the load and likely increase the voltage depending on what the load is.

resonance (capacitor across the load): In this mode there is a capacitor somewhere. Maybe the load is a capacitor, there is a capacitor inside the transformer (self resonant frequency), in the case of a CRT monitor the capacitor is placed across the transistor. Transistor=on, current builds up with time. Transistor=off, current stored on the core inductance will move onto the capacitance as voltage. I^2L/2=V^2C/2 Running slow will increase the voltage!

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