4 bc639 transistors are used in fan speed control circuit and speed can be adjusted with 47k trimpot on the circuit. Intel CPU fan used in circuit tests is a low cost simple circuit for begi... Read more
There are 41 applications on TTL digital doors. I am thankful to our readers, S.Demirhan(sdmh), who brought the file to me . Many of the circuits have been tested and Vocational High School... Read more
This circuit board can be used for single channel 50w output circuit board sizes are small, and the layout of the feeder can be symmetrically 2 × 10 volts 2x 30 volts smoothly and the layout... Read more
Installations with restricted access are often protected using an access code. If you don’t have particularly demanding requirements regarding modifying the code, you can manage quite nicely... Read more
Mechanical contacts have the disadvantage that they wear out. That is why it is practical to use an electronic ‘touch switch’ in some situations. With such a touch switch the resistance of t... Read more
There are only a limited number of switching regulators designed to generate neg-ative output voltages. In many cases, it’s thus necessary to use a switching regulator that was actually desi... Read more
Sometimes you have to do it the hard way, even if doing it an easy way is an option. That is the case here. The intention is to add a second doorbell in parallel with the existing bell. This... Read more
It features at least once in every Small Circuits collection: the 555 timer. In this simple circuit we give the chip a little more attention than usual (refer to ‘The Eternal 555’ in the Jul... Read more
For a few pounds, you can buy a kit from any automotive accessory shop that will allow your car to be fitted with a central locking door system. Such a kit essentially comprises a number of... Read more
In order to connect the open-collector output of a standard Conrad DCF receiver module (order number 121177), which has a relatively low operating voltage of 1.5–15 V and an NPN open-collect... Read more