This high voltage source, found in 90’s Popular Electronics, can reach tens of thousands of volts. The Q2 transistor must have an excellent heat sink and the 9 V source is high current.
Written in an article in Radio Electronics magazine in April 1987, this circuit triggers an alarm...
This is the receiver circuit for the previous transmitter. The circuit has a programming key to...
This is an example of a temperature sensor shield using the Texas Instruments TMP390 obtained from...