A few months back, frequent DI contributor Nick Cornford showed us some clever circuits using the TDA7052A audio amplifier as a power oscillator. His designs also demonstrate the utility of the 7052’s nifty DC antilog gain control input: ...
Another day, another dodgy device. This time, it was the continuity beeper on my second-best DMM. Being bored with just open/short indications, I pondered making something a little more informative. Perhaps it could have an input stage to amplify ...
An adjustable load in Figure 1 provides a constant-current load for testing power supplies and batteries. It allows you to set the load current to up to 1.05 A, using a potentiometer, and displays the current on a three-digit LED display controlled ...
Meters that indicate analog levels via a moving-pointer meter, a numeric display, or a column of LEDs typically occupy considerable panel area and require more than a casual glance to read. An indicator lamp or LED takes little space but indicates ...
In the first part ( Ref. 1 ) of this Design Idea (DI), we saw how to use the TDA7052A (or similar) power amp to build a minimalist siren-type power oscillator, and also, having looked at that device’s distortion characteristics under various ...
The voltage booster is a 'true' charge pump. When the output of the 555 is low, C4 charges from the supply via D1. When the output goes high, the positive end of C4 is forced high (to +24 V in a perfect world), and the charge is transferred ...
Introduction These ultra-simple projects are intended to provide two simple functions without the need for transformers or 'esoteric' parts. The first is a simple charge-pump voltage booster, that will raise your supply voltage by a factor ...
Electrets aren’t only used as audio pickups. For decades, they have been employed in security systems to detect unexpected changes of air pressure within rooms, while more recently they can be found in vapes as suck-sensors (or, more ...
This design idea reprises another “1 A, 20 V, PWM controlled current source” ( Ref. 1 ). Like the earlier circuit, this design integrates an LM3x7 adjustable regulator with a PWM DAC to make a programmable 20 V, 1 A current source. It ...
Rheostats Rheostats are simple and ubiquitous circuit elements, usually comprising a potentiometer connected as an adjustable two terminal resistor. The availability of manual pots with resistances spanning ohms to megohms makes the optimum choice ...