Electronics Design

Power inverter designs

A power inverter, or inverter, is a power electronic device or circuitry that changes direct current (DC) to alternating current (AC). The inverter does not produce any power; the power is provided by the DC source. This document is collection of information on power inverter technology and gives links to DIY circuits – both good

50 ohm vs 75 ohm conversion

Coaxial cables are measured by impedance. The most common impedance values are 50 ohms and 75 ohms. different cables. 50 ohms is most often used for radio transmitting and receiving applications. 75 Ohm is primary used for video and audio. 75 Ohm cables are the standard coax cable you find everywhere inside your home and

Calibration of multi-meters

I saw this question posted to ELECTRONICS HOBBY CIRCUITS IN FACEBOOK group: “can you tell me what is the meaning of calibration date of a multimeter and does it effect the work of a multimeter if it expires the calibration date?” The answer to this is: As all circuits will drift with time, the DMM

Capacitor testing

Test with multi-meter that it is not short circuited. Test with capacitance meter that capacitance value is correct. If this is an electrolytic capacitor I measure ESR. With some electrolytics I charge them to nominal voltage with power supply and measure charging leakage current or the rate it self duscharges. If it is a small

Short circuit protection

Facebook post at https://www.facebook.com/groups/electronichobycircuits/permalink/3743513689006646/ advertises this circuit idea: Amazing Idea With Relay & BC547 Transistor https://techsawco.com/amazing-idea-with-relay-bc547-transistor/ I see this circuit much less than amazing. “This circuit is used as voltage level indicator and short circuit protection circuit.” Voltage level indicator idea is feasible. The “short circuit protection circuit” does not live up to the promises

ESR meter DIY

One way to test electrolytic capacitors is to measure their capacitance. It does not tell the whole story of capacitor condition. Another usually more useful way to measure electrolytic capacitor condition is to use an ESR meter. Here is ESR meter I built years ago based on instructions from http://ludens.cl/Electron/esr/esr.html but I built the transformer

DT830 multimeters

Saw in Facebook discussionhttps://www.facebook.com/groups/electronichobycircuits/permalink/3657982357559780/ https://www.facebook.com/438304376511718/posts/1304575383217942/ Another meter is fried again today!!! I have six meters blown in 2 years, while reading high voltage AC. I guess I will find a better alternative for such reading. Is there a way of fixing spoilt meters!?. We are talking about this kind of DT830 type multimeters: My answer:

Linear power supply rectifier designer

LINEAR POWER SUPPLY DESIGN ASSISTANT #1 at https://www.changpuak.ch/electronics/power_supply_design.php is a tool for designing and simulating linear power supply rectification and smoothing capacitors See the circuit diagram. Enter the design data and can see the output voltage ripple and current on circuit. You can try with different capacitor values, different loads and different transformers. This is

Night light teardown

Here is a teardown of cheap mains powered LED night light from LIDL. After few years of use this light became very dim and so useless. I opened it to see what is in it and what was broken. Let’s open it. Circuit board details Here is the circuit diagram. This is quite typical transformerless