This percussion circuit was found in an Electronics World of 1968. The transistor may be general purpose and the power supplied at 12 V. The signal must be applied to an amplifier.
This simple test lets you measure zener voltage. The power must be higher than the diode tested...
We found this setting in the Texas Instruments opto-electronics manual. The bipolar can be the...
This circuit was published in a 1979 magazine, but it can still be easily assembled, as the...