rickyjar
Member level 2
User “maxdila” presents his 0-32V ~ 7A laboratory power supply with a LC-meter to replace the old one based on Lm317.
The concept includes:
- a power supply with a continuously variable output voltage adjustable from 0-32V and output current limiter 0.002-7A
- DS18B20 temperature measurement
- capacity measurement from 1pF to 100mF
- inductance measurement 0.001uH - 100H
Casing:
- made of aluminum, powder-coated
- the rear: profiled metal sheet, powder-coated
- the front:14mm flat bars milled in order to hide the electronic appliances and black-anodized
Cooling:
- a 192x70x50mm heat sink with a milling for a 12V fan, black-anodized
- a fan driver based on lm317 + 4k7 thermistor
- on the heat sink 3xTIP3055 + 3x0R22 (emitter heat sinks), 2x 0R47 5W in a metal casing, thermistor and DS18B20 temperature meter
Power supply module:
- 200W 24VAC transformers
- an additional 1k potentiometer to regulate voltage more precisely
- the modified system from https://www.electronics-lab.com/projects/power/001/index.html:
-> BD139 with a heat sink in place of 2N2219
-> 0R235 (2x 0R47) instead of 0R47 – current up to 7.5A
-> 3x TIP3055 instead of 2N3055
-> C1- 10000uF/63V instead of 3300uF
-> 8A rectifying diodes
Controlling:
- 12V and 5V server power supply to power the fan, relay and meters,
- a 10k potentiometer (voltage regulator) with a switch supplying the 12V relay switching the transformer on
- the main power switch placed on the illuminated panel
V/A/'C meters:
- the system bought online, the voltage and current meters with the possibility to measure temperature and a power indicator, readings displayed on a 2x20 display consistent with the HD47...
- a 4rech shunt of 0R1 heat sinks connected in parallel
- the possibility to measure Q (charge)
L/C meter:
- the system from ChRL
Whole:
- temperature was measured by switching to the external sensor, all because of the MiniJack switching between 2 connectors (in this case Vdd and DQ, common mass for both sensors)
- 3 banana sockets, from the top 5V, 12V , 0-32V
- the possibility to disconnect a transformer with the potentiometer voltage regulator
- cooling regulation set at the maximum of rotations in 40°C
- the internal sensor obviously measures temperature of the heat sink
- 3 TIP systems were used on account of heat distribution and lesser chances to destroy the transistor
- descriptions are planned to be made with Dymo Label
- a negative green display is better than black one in terms of readability
- there is still much space for additional systems in the casing
- the heat sink is elevated towards the bottom board, which ensures airflow inside the casing
- the power cord is placed underneath the casing
- the maximum temperature (in the room 17°C) reached 45°C after 10 minutes while 10V and 7A
Link to original thread -Zasilacz laboratoryjny 0-32V ~7A z Miernikiem LC
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