Equivalent of an A55 Transistor

On 2012 Apr 11, at 3:15 AM, Rob Jarratt wrote: Generally you want the hFE to be same or higher. Gains vary widely even for the same type of transistor, the hFE spec is a minimum, the usual idea is the design will need a minimum gain to work and variation will be dealt with through either feedback to fix the gain at a designed level (analog apps), or base-current overdrive (switching/digital apps). A couple additional comments on transistors: - That there are tens of thousands of transistor types has more to do with history and manufacturing processes and economies than it does with functional necessity or distinction. This is displayed by the replacement-transistor suppliers such as NTE/ECG which are able to operate by mapping the specs for those tens of thousands down into a few hundred different types. - The suffix letter can mean many things, I expect it may even mean different things for different manufacturers. For OnSemi it appears the G suffix (MPSA55 vs MPSA55G) indicates the lead-free variant. I ran across a situation recently where the suffix letter indicated a different pinout (EBC vs ECB) on the same TO-92 package.