A Zener diode is the simplest known type of voltage limiter (Figure 1) As soon as the voltage exceeds the rated voltage of the Zener diode, a current can flow through the diode to limit the... Read more
Ever wanted to build a positioning encoder? Here’s one and you do not even need any sensors. The circuit uses an LED as a light emitter and another LED as a light receiver. This is possible... Read more
This is a tried and trusted design for the protection against overvoltages that can be configured for your own needs. The circuit can also be used to detect under voltages; in that case, the... Read more
This circuit should be considered as more of an experimental circuit for AM demodulation, than as a practical application. In the associated ‘AM modulator’ we have raised the problems caused... Read more
I’m in the process of building myself a single-ended class A MOSFET amplifier consisting of two monoblocks, and I don’t want to use a coupling capacitor between the amplifier and the speaker... Read more
Rotating laser levels, which are very handy for setting objects in a room or garden at the same height, are available at prices of a few dozen pounds. At relatively large distances and for o... Read more
The simplest way to make an adjustable constant current source is to use a voltage regulator in a suitable configuration: an example of what is needed is given in the LM317 datasheet. Howeve... Read more
When testing circuits and fault finding there is often a need to inject a defined DC voltage level at some point on the circuit. It may, for example, be necessary to apply a logic level on t... Read more
The circuit described here provides monitoring of the charge status of a battery by the continuous measurement of charge and discharge currents. The battery current is integrated over time (... Read more
This design resulted from the need for a partial replacement of the well-known 8038 chip, which is no longer in production and therefore hardly obtainable. An existing design for driving an... Read more
