On 5/31/26 11:20, David Wade via vcf-midatlantic wrote:
Thanks folks! I have a spare step-up transformer. I just wasn't sure if providing the UK Atari STE a 240V / 60 Hz power source would be a problem as it's probably designed for a 240V / 50 Hz source.
Its a switched mode PSU so the first thing that happens is that the mains is rectified and used to charge a high-voltage capacitor. So I think it will be fine with 240v/60v.
Really the usual cause of problems is running a US designed setup on 110v/50hz. Transformers efficiency depends on frequency, which is why a SMPSU which runs a kHz can have such a small transformer
I'm sorry Dave but this is wholly incorrect. Switching power supplies typically don't use transformers to step down voltages; they chop the rectified incoming voltage using a chopper transistor driven by an oscillator, and control the pulse width such that the integrated voltage (area under the curve) is the target voltage. An integrating network and filtering follows the chopper to produce a steady DC voltage, and a voltage divider pick-off is compared against a reference voltage and used to control the PWM width in a feedback network, resulting in regulation to the desired output voltage. It is not a matter of converting the frequency higher so a smaller transformer can be used in a linear power supply arrangement. -Dave -- Dave McGuire, AK4HZ New Kensington, PA