I was looking for a good supplier the last days and I’m afraid that the best chances to obtain these is via EBay, just like Guenther mentioned.
Theres still a chance however, I know a firm here in Belgium who may still have these Original transistors on stock.
I will make a call tomorrow and ask about the price.
I will post then here the price with shipping to you.
If some one else is also interested, let me know.
Please consider that the AC125 transistors have a Max. collector current of 100mA.
The AF125 transistors have only a 10mA current and may never be used to drive replays, lamps, speakers.
Most circuits of the original Lectron manual lack safety resistors. Be sure to Always use a resistor of min. 47Ohm in series with the light bulb.
Depending of the model of relay used, this may also need a resistor.
If you want to be on the safe side when you are constructing a circuit, use a 47Ohm or 120Ohm resistor connected in series with the battery.
With a 47Ohm resistor, the max. Current flowing will be then 200mA.
With a 120Ohm resistor, this will be then 75mA.
An advantage of using a battery over a power supply module is that a 9V battery is limited in delivering current.
Please check the experiments published in this forum for more details about these protection methods.
Always double check the circuit for errors.
Your transistors (and other components) will benefit from these protection measures.