I'm trying to figure out what this diode is.

The marking indicates "A7" and also has "t36" stamped on it suggesting maybe a 1N4007 rectifier diode.

However, when I test it with my multimeter I get a forward voltage of 0.05v and reverse voltage of 1.7 V. Forward resistance of 107 Ω and reverse resistance of OL. Nothing out there seems to match these low values. I was thinking that it's a Schottky diode, but I'm at a loss. The circuit is for a small low power radio transmitter. Below is the schematic and a picture of the diode itself.



  • \$\begingroup\$ You're measuring them in-circuit aren't you ... ? \$\endgroup\$ – brhans Jun 13 '19 at 17:28
  • \$\begingroup\$ Yes? Is that a no no? \$\endgroup\$ – Britt Smith Jun 13 '19 at 17:36
  • \$\begingroup\$ I took the diode off the board and there was no difference. \$\endgroup\$ – Britt Smith Jun 13 '19 at 17:46
  • \$\begingroup\$ Was this reverse voltage of 1.7V also there when you removed the diode from the PCB? BTW, seeing your capacitor values: you neither can just measure capacitance in-circuit \$\endgroup\$ – Huisman Jun 13 '19 at 18:23
  • \$\begingroup\$ Yes, 1.760v to be exact. 10-4 on the capacitors. I'll remove them and measure. Note: the board is not connected to the batteries currently and is disconnected from the rest of the radio transmitter circuit. \$\endgroup\$ – Britt Smith Jun 13 '19 at 18:37

It likely is a 1N4007 clone, e.g. made by Zibo Seno Electronic Engineering Co., Ltd. or by by Shenzhen Jingxin

| improve this answer | |
  • \$\begingroup\$ Hi, I'm still perplexed by this. I ordered some 1n4007 diodes and they measured like a normal diode should (0.5 forward voltage). Could it be a switching diode? I also ordered a kit of THT diodes and the Schottky 1n5817 seems to be closer to the values I'm measuring in terms of forward voltage and resistance, but the Schottky diode is still greater. \$\endgroup\$ – Britt Smith Jun 28 '19 at 13:17

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