This circuit, obtained from a 1965 magazine, can still be assembled using some modern equivalent components. The transistors may be BC558 and the transformer is obtained from a disused transistor radio.
July 2017 - The new TLP240 and TLP241A optical couplers with MOSFET output, manufactured by...
This circuit makes use of a PLL 567 and the components must be calculated according to the desired...
This 80's circuit has an input resistance of the order of 880 M and gain 10, using operational...