The presented circuit uses a PNP transistor, which can be the BC558. Observe the polarity of the supply. The circuit is suggested by Texas Instruments opto-electronic documentation.
June 2016 - It can be obtained from the Mouser the MIROE 2253 that converts text into voice.Trata is a...
Instead of the lamps, LEDs can be used in series with 470 ohm resistors. The circuit is from an...
This very low frequency amplifier has a gain of 1,000 and was found in a 1967 documentation. The circuit is...